Ah ok, so are you guys saying that you are "converting" the final stats of after applying the actual stat multiplied by 1.5 into a base stat equivalent?
Yeah. To find the equivalent base stat, you calculate out the final stat of the Pokemon, multiply it, then figure out what base stat would give that value with the same EVs/nature. For prevo stone, you'd be multiplying by 1.5.
A classical example is Azumarill from DPP UU.
50*2 + 252/4 + 31 +5 = 199 (stat calculation)
(199+19)*2 = 436 (nature and Huge Power)
436 - 39 = 397 (correct for nature)
397 - 5 - 31 - 252/4 = 298 (correct for EVs/IVs)
298 / 2 = 149 (final base stat)
So 252+ Azumarill has an equivalent base attack of 149. Yup, that little blue mouse has Groudon-level attack.
BTW, the equivalent base stat varies based on how many EVs you put into the stat.
Also, since prevo stone precludes the use of leftovers, I'd say you should knock 10-15 off those equivalent base stats when comparing to other Pokemon. Eg, max mixed bulk Dusclops has 40/212/212 effective base defenses. However, his inability to use leftovers means that, for comparison purposes, they're more like 40/200/200.