Hello guys, I've got quite a long and complex question that I would like to ask.
SO a friend of mine and I was running some tests with priorithy moves earlier this evening. My theory was that a Gengar with the move sucker punch using black glasses (20% dmg boost to dark moves) would deal more damage than a technician (50% dmg boost to moves lower than 60 atk power) scizor using bullet punch together with the item metal coat (20% dmg boost to steel moves). Due to my calculations Gengar's sucker punch would reach 96 atk power and scizor's bullet punch 72 atk power.
Gengar's sucker punch : 80 atk power (base) x 1.2 (black glasses) => 96 attack power
Scizor's bullet punch : 40 atk power (base) x 1.5 (technician ability) x 1.2 (metal coat) => 72 attack power
Now to the testing session. We used both Gengar and Scizor on the same pokemon which was neutral to both moves and with no buff moves. The pokemon we used was a Garchomp with approximately equal def and spdef. Scizor's base atk was 390 and Gengar's base spatk was 360. The result of the test was that Scizor dealed about 50% hp dmg on Garchomp and Gengar only dealed 15%, even when Gengar's move sucker punch had clearly higher attack power.
So after this tl;dr I am simply wondering, why did Gengar dmg so poorly compared to Scizor even tho he had higher attack power on his move?