From reading the forum about the brain builder (and obviously everything that applies to the brain builder also applies to the muscle maker), its common for people to use brain builders to raise the stat maximum intelligence for their half-ogre characters So obviously the brain builder/muscle maker can raise stat maximums of the raised stats up to the normal limit of 20 So my question is do brain builders/muscle makers lower the stat maximums of the lowered stats? Example: Say a Human with no background uses 7 brain builders, is the maximum str/dex/con/be that you can reach with character points 20 or 13 (8-7+12)=13
Yes they do; if you put points into any of the physical stats after using 7 brain builders with a human they would all be capped at 13. However you could always use muscle makers to reverse the change. Also, though I'm not entirely sure, I'd think that temporary therapeutic stat boosters (the vivifier, the energizer, etc.) could be used to raise stats above the new caps introduced as I used these to boost a past half-ogre character's intelligence to 20 and his strength to 24 (I was using the rare half-ogre birth background so his strength was capped at 23 and his intelligence at 18).
One thing I would change in your post, Jojobobo, is noting that the Vivifier's effect is not temporary but permanent.