Crothian said:
No good reason? Characters get a +1 bonus every 4 levels. If I have odd ability scores I can get a useful boost at 4th level. I always have odd abilites when using point buy. My dwarf fighter has a 15 strength and a 17 con, just so at levels 4 and 8 I can boost them and get something worth while.
Your dwarf would do better off with 16 Strength and 16 Con (or alternatively, 14 Strength and 18 Con).
My way:
16 16 1-3
16 17 4-7
16 18 8-11
Your way:
15 17 1-3
16 17 4-7
16 18 8-11
Or alternatively:
My way:
14 18 1-3
15 18 4-7
16 18 8-11
Your way:
15 17 1-3
15 18 4-7
16 18 8-11
So, levels 4 to 11 are identical, but levels 1 to 3, your Dwarf had +1 to hit and +1 damage less than mine (or 1 hit point per level and 1 less Fort) and hence had less of a chance to survive.
I'm willing to entertain other reasons, but I have never thought of one that is actually strong. For example, having odd stats so that if you get odd ability score drained you might drop fewer actual mods is an extremely weak rationale as well.
The only two even vaguely valid reasons I can think of are:
1) Your way gives the option at level 4 to up either Str or Con (i.e. to choose at level 4 which is more important) and quite frankly, I'd rather have the boost to one of those two stats for 3 levels, more than having that option (which isn't typically worth that much).
2) Having a 13 Dex or 13 Wis (or somesuch) in order to qualify for feats. Again, the chances of you developing a character that requires BOTH Dex and Wis 13 before level 4 seems extremely rare and less of a benefit than having that extra boost in one of the two stats. Yes, you might have a rare character concept that needs this, but I suspect it would be extremely rare.
So yes, someone might have an unusual reason for doing this, but not just to actually gain something at both level 4 and level 8. That's counter-productive.
In 3E, buff spells was the main good reason. In 3.5, they took that away and there aren't any really strong reasons remaining.