Not to be rude, but your logic breaks down to:
Resist Fire and Resist Cold can work together because Resist Fire and Resist Cold can work together.
Eexactly
If I cast False Life and roll a 3 on my D10, then cast it again to try for a better result and roll a 1, which one applies? The answer is 3. They don't "stack", you get the higher result.
That's the exception to the "usually" you highlighted.
That is not so. False life is not subject to this rule.
Multiple False Life-s do not produce "varying effects", they produce "different strengths" of the same effect.
False Life is subject to:
Same Effect More than Once in Different Strengths
In cases when two or more identical spells are operating in the same area or on the same target, but at different strengths, only the best one applies.
In PHB the text continues with an explicit example on
Ray of Enfeeblement (PHB, p172).
The fact that the spells explicitly say you can't combine Resist and Protection spells for the same energy is actually irrelevant to the discussion. That's a specific prohibition, independent of the topic at hand. It might just as well have said that you can't use one of them on a Tuesday.
The text does
NOT explicitly say you can't combine
Resist and
Protection spells for the same energy.
It explicitly says that you can't combine
Multiple sources of the same energy type.
Very Different from what you say, and quite relevant indeed.
Multiple sources means anything from "the same spell", to "a spell & a racial/class ability"
So again:
Multiple sources of resistance to a certain energy type don’t stack with each other
=
Multiple sources of resistance to a different type "work" with each other.
Now lets go back to Same "Effect with Differing Results".
Since False Life is not the exception to the "usually", lets see which spells are.
1-Comprehend Languages
The spell enables you to understand or read an unknown language, not speak or write it.
Under "Effect with Differing Results", you can cast Comprehend Languages on the same target multiple times.
The fact that he now understands yet another language, does not trump the fact that he understands another language (ability provided by a previously cast Comprehend Languages).
2-Blindness/Deafness
You call upon the powers of unlife to render the subject blinded or deafened, as you choose.
Under "Effect with Differing Results", you can render a subject both blind and deaf, because being blind, does not trump being deaf, and vice versa. (even though the spell is Permanent, it is also (D), which means it is not a one off magical effect).
3-Mnemonic Enhancer
Casting this spell allows you to prepare additional spells or retain spells recently cast. Pick one of these two versions when the spell is cast.
Prepare
You prepare up to three additional levels of spells. A cantrip counts as ½ level for this purpose. You prepare and cast these spells normally.
Retain
You retain any spell of 3rd level or lower that you had cast up to 1 round before you started casting the mnemonic enhancer. This restores the previously cast spell to your mind.
In either event, the spell or spells prepared or retained fade after 24 hours (if not cast).
Not any combination of the spell's versions trumps another.
4-Resist Energy
This abjuration grants a creature limited protection from damage of whichever one of five energy types you select: acid, cold, electricity, fire, or sonic.
Under "Effect with Differing Results", being protected from fire does not trump being protected from cold.
.....there are more examples of course................
And now lets see when this "Usually", DOES apply.(because a latter effect trumps the former one).
1-Disguise Self
You make yourself—including clothing, armor, weapons, and equipment—look different. You can seem 1 foot shorter or taller, thin, fat, or in between.
Under "Effect with Differing Results", whenever the new form/texture/color etc. specified trumps the former one, the latter specification prevails.
2-Alter Self
You assume the form of a creature of the same type as your normal form. The new form must be within one size category of your normal size. The maximum HD of an assumed form is equal to your caster level, to a maximum of 5 HD at 5th level. You can change into a member of your own kind or even into yourself.
Under "Effect with Differing Results", the new form trumps the former one. The latter form prevails.
The same stands for all related transmutations:
Polymorph, Polymorph Any Object, Shapechange.
3-Suggestion
You influence the actions of the target creature by suggesting a course of activity (limited to a sentence or two). The suggestion must be worded in such a manner as to make the activity sound reasonable. Asking the creature to do some obviously harmful act automatically negates the effect of the spell.
Under "Effect with Differing Results", whenever the latter suggestion trumps the former one, the latter takes precedence.
The same thing stands with:
Geas-Lesser, Geas/Quest, Demand.
4-Secret Page
Secret page alters the contents of a page so that they appear to be something entirely different. The text of a spell can be changed to show even another spell.
Under "Effect with Differing Results", the latter altered-content trumps the former one. The latter altered-content prevails.
5-Control Weather
You change the weather in the local area. It takes 10 minutes to cast the spell and an additional 10 minutes for the effects to manifest. You can call forth weather appropriate to the climate and season of the area you are in.
Under "Effect with Differing Results", the latter weather conditions trump the former ones. The latter weather conditions prevail.
.....again.....there are more examples of course................
But Resist Energy is a single spell, no matter which energy type you apply it to. Same for Endure Elements and Protection from Energy spells.
No. Resist Energy is a single spell that can produce "varying effects". So can Protection from Energy.
Endure Elements is totally different.
Endure Elements does not produce "varying effects". It always protect the subject from ALL conditions at the same time. You do not get to choose the conditions.
The specific question is, can you cast the same non-instantaneous spell multiple times on the same target and gain the full benefit each time? The answer is no. It's written quite clearly that you can't.
The answer is no?
Honestly, I do not see anywhere, anything "clearly written" that says that you can't.
What is written quite clearly is this:
Same Effect with Differing Results: The same spell can sometimes produce varying effects if applied to the same recipient more than once. Usually the last spell in the series trumps the others. None of the previous spells are actually removed or dispelled, but their effects become irrelevant while the final spell in the series lasts.
=
Same Effect with Differing Results: The same spell can sometimes produce varying effects if applied to the same recipient more than once. Usually the last spell in the series trumps the others (usually, the latter effect trumps the former one). (When that usually happens) None of the previous spells are actually removed or dispelled, but their effects become irrelevant while the final spell in the series lasts.
Perhaps you do not agree with the above translation?
IMO, this is the only translation, and that is so, because otherwise, the word "
Usually" does not make ANY cense whatsoever.
How am I to interpret this "Usually", if i do not deduce that it refers to the subjectivity of "when does an effect trump another?".
Based on what, am I to figure out when this "Usually" happens...if i do not compare the effects, so as to conclude on what trumps what?
It even goes so far as to say that you can't, even if the spell produces a different effect each time.
Please, point me out the phrase where this is written.
The example they give isn't specific for Resist Energy spells, and implies a reasoning that makes sense for Polymorph and not for Resist Energy, but they can't always make examples out of the exact spell issues we're interested in at the moment.
Exactly. They can't always make examples out of every case. This is why the included this "Usually", so that gamers employ reason and logic so as to figure out what trumps what.
Again, if you disagree, I'm eagerly awaiting for your interpretation of this "Usually", for I fail to see any other than the one I explained above.