Power Level debates aren't about stacking, they're about percentages.
So say there's a power level gap of 700 to 747 or basically 70/75 & 14/15 or 6.67% & 93.33% of 100%, that would be in the moderate rivalling range, at least in my opinion (distant rivalling gaps would be 90% of 100% and close rivalling gaps would be 95% of 100%).
In cases of where the opponent has the edge over you, it would be anywhere from 80% to 88% of 100%, and when it comes to stomping ranges, it would be anywhere from 60% to 75% of 100%.
I consider any power advantages in special cases like Initial Semi Perfect Cell over Android #16, Warming Up Perfect Cell over USSJ Vegeta, and Imperfect Cell Post Absorbtions over Kamiccolo, to be 50% of 100%, 40% of 100%, and 33% of 100% respectively, but again, this is just my opinion.