I must be missing something
Simple example:
Scorpion's Xray does 30% as a stand alone hit. Now consider these 2 simple combos.
1,1,spear,Xray does 3,5,3,25 % damage for a total 36%. From this combo it appears that the Xray loses 5% total for being the 4th hit in the combo.
Now B+2,spear,Xray...