Beast's Mastermind Synergy Doesn't Stack?

Why doesn't Beast's Mastermind synergy stack?

15% Attack increase after a 15 hit combo. So with two Beast's it should be a 30% Attack increase after a 15 hit combo.

My friend tested with his 4* and 5* with a SIM and the synergy didn't stack.

The original 15% didn't even work correctly. It was closer to 14% according to the math.

Comments

CoatHang3r

There are factors like armor that prevent you from seeing the exact percentage for attacks. What you want to do is take his base bleed damage (or direct damage from awakened ability) from the profile and figure out what 15% is then compare the value difference with and without the synergy attack modifiers.

Flash_Asher

That's where I got my basic numbers from bro. Bleed damage. Used a champ that doesn't proc buffs like fury against a champ that doesn't proc buffs like armor or anything else that could alter the numbers. Guess what? Still 14% not 15%, especially not 30%.

Jokepool

Just got a 6 star beats and have the same question
I dont think his basic attack will change, but cause the increase damage just prop wen you do more then 15 hits
I test it and it seems its not working properly
And other thing.. If you put a beast/beast/BP/Superior IM in the team the should be a 60%increase right?