@blindcoder Hey!
Percentages in Rocket Rats don't work multiplicatively but additively. For example, if you have 10 ammo, take 50% and go to 15, then take 100% you won't go to 30, but instead to 25. Since the sum of percentages is 150% and 10 * (1 + 1.5) = 25.
In your case you probably already had a buff of 100% and got another one of 100%, adding plus 8 which is the base number.