What mistake?
I think my experience is far more common than yours. That is not a mistake.
Ok.
No. Minions are killed with area effects.
Maybe, maybe not but typically not. They are drained with AOEs.
Give me a hard encounter with many minions that are actually "killed" with an AOE. You claim this happens, provide an example, it is pretty easy. Maybe a bunch of Goblins guarding a Lich would do it!
You are the one arguing that favoured foe is better although the way you use it you can just leave it away as the difference is neglegible over your adventuring day.
This is not relevant to the bit of text you quoted. Sounds like you are going to a different thread to bring up something that is not relevant to the discussion we are having here.
If you want to take about Favored Foe vs Hunters Mark, I will happily do that, but make a statement and I will answer with details and if applicable statistics and number. However bringing up unrelated stuff from other threads without any sort of context is not relevant to the discussion we are having here.
Nope. You use it. But correctly. Mark the big baddie.
If you cast conjure Barrage you do not get any damage from Hunter's Mark for that round. This is a fact unless you have a spell that gives you another action and even in that case it is a small amount (3.5 damage on a hit).
Nope. Better use conjure barrage than hitting them.'
To say again what I said earlier (note the underlined):
"IME in play, the number of rounds you get to use it without casting/moving it is less than the number of rounds you need to use a bonus action for it, and they are not really even close. Now a lot of times you do forgo moving it to use a different bonus action or the marked person is still alive but you either need to attack another enemy (someone else is near death or the guy you marked teleported away or something) or you need to do something else on that turn rather than attacking. But in any case it is relatively uncommon in play that the Mark is already sitting on the enemy you attack for all your attacks."
If you cast Conjure Barrage on that turn you are not using Hunter's Mark that turn.
That is not how math works. 4 vs 1 kills the one guy faster than 2 vs 1
Not if the encounter is balanced at the same level it doesn't.
4 3rd level characters against one Young Green Dragon does not end faster than two 3rd level characters against one Red Dragon Wyrmling even though they are both "deadly" encounters.
You don't understand how the math works.
Focua firing and not focus firing make big differences.
Yes it does and as a Ranger using Hunter's Mark you will often be faced with a decision - get the most out of Hunter's Mark or Focus Fire.
And it is easier to focus fire on ranged attacks which conveniently usually leave your bonus action free.
Assuming you do not misty step or are playing a race or have a feat that uses a bonus action or have a subclass that uses a bonus action, or have a multiclass that uses a bonus action .... oh and you did not go with crossbow expert either for your ranged attacks (i.e. the highest damage ranged build).
Yes if all of those things are true you will not lose much by using your bonus action to move the mark every turn.
You are really mixing up average and actual kills.
Assume 4 foes with 40 hp. Assume PCs with 10 damage.
This is a poor assumption. The only time PCs have 10 damage is like 1st and maybe 2nd level (but not really even 2nd level). Your damage assumptions have to scale with both level and with expendable resources since more resources will be used in harder fights.
You mentioned Conjure Barrage. That will average 17 damage per enemy hit. Assuming 2.5 enemies in the AOE on average that is over 42 damage from one action in one round!
In a 1 vs 1 it take 4 rounds to kill one enemy.
My 1st level party of 5 wiped out 4 bandits (11 hps each) and one bandit leader (65 hps) in 3.5 rounds last Thursday.
The same party of 5 1st level characters wiped out an Ogre-like Monster (59 hps I am guessing) in less than two rounds. It never even got an attack!
Non focus fire means no matter how big the party, every foe lives 4 rounds. Then all die at once. No HM shifting.
Ok the math is off, but the idea is good. So focused fire over 4 rounds the enemy gets 10 turns (4+3+2+1). If you split, it still ends in 4 rounds but the enemy gets 14 turns (4+4+4+2) .... this assumes 2 enemies die on the last round before their turn.
So the enemy will have done 40% more damage to the party in the second case during that fight. So sure you got all your HM damage in and the part is worse off for it.
Usually focus firing one enemy is nearly impossible. Maybe some 2 vs 2s. So after 2 rounds one enemy dies and after 2 round s the next one. So only using HM shift every other round.
Yes it is often situational and can be difficult. I would not say impossible though, and I think in general it is easier to focus fire than it is to attack the specific enemy you already have marked and alive.
More to the point though the exact same factors that would prevent you from focusing fire on a single enemy also often prevent you from attacking the one enemy who is marked.