Cannon damage (5% more) not calculated correctly

Hello,
My cannon made 800 points of damage. I trained it to level 32 (last level), which means it would make 5 percent more damage. But the cannon stays at 821 damage instead of 840 which it is the damage I think it should be. Looks like the improve is 2,5% instead of 5%
Am i missing something? Is that correct?
Thank you in advance!

 

Talent % only improves the base stat

 

5% more damage from a talent will only increase by 5% of my base stat that is 771

 

(Without any damage perk)
( x = base damage )

 

Thank you, now I see, it's right then.