No, it's fine. Guess I just misread about the M.P. part.

But there's only so much room on the sphere grid. If you want 99,999 H.P., then you're probably not going to have enough room left over for your desired amount of increase in the luck stat. I'm not really clear on this: do you want 99,999 H.P. for just the battle, or do you want 99,999 H.P. overall? Because there are far easier ways of attaining that much H.P. in a battle (Rikku's Mix).

Concerning the thing that I said earlier about your luck in relation to your accuracy, evasion, and agility, I think the thing about having 170 agility is true, but mine is 255 on all my characters just because I wanna make sure that I'm getting the most speed I can. But it all comes down to which stat you want to raise. You can spend an exhorbitant and unnecessary amount of time raising your luck and H.P., or you can have it go faster by having half as much H.P. overall (but still being able to use Mix to get 99,999 H.P. during the battle with Penance itself).