i just go with the rolls, never redo level up just because of hp, what i get is what i get. I certainly know ellana isn't maxed out, with a 14 con, toughness, at level 14- 7 rogue/6 fighter/1 cleric. . .maxed i would have about. . .eh. . does math.
154 i think, yes. But, just going with rolls she has about 138 or 136. . .granted the few hp might be a little helpful, but i honestly don't think it matters. For those constantly training there is toughness, though thats as far as it goes with out epic levels.
It is possible, of course, to allow such feats, but that is up to the dev team i think if they want to make such available to people under lvl 20.