My level 6 barbarian is only getting +2 Str when entering rage and the Temp Hp is only adding +8 when he has a 14 Cha. Seems right IMO, but the documentation says the HP is Cha *2 not Cha Mod *2. Also the temp hp seem to stay until enough damage is dealt to remove them otherwise they appear permanent.
Fixed. It's charisma modifier.
Yep appears to be in working order, thank you.