Ok I see your Problem. When you are adding your 10 points to your Abilities at creation, Change the Base Value (not the mod value). That will update things correct.
(This did not fix his issue ( The bonus number is not changing after first writing. )
Also I have just posted in the Known bugs thread about a upcoming update to the Key Ability System.
https://www.fantasygrounds.com/forum...l=1#post380190