“Stop calculating, Boss,” Zorba continued. “Forget numbers, break those disgusting scales, close the grocer’s shop.”
Yes if VS71 was saying that in a "logical" / "calculating" way totally, then I think your concern would be valid. But Epicurus makes clear that the only criteria is pleasure and pain, and those are feelings, not widgets or numbers that can be absolutely quantified.
I would even say that that has to be kept in mind in considering the "natural and necessary" evaluation. Other than food, water, shelter, clothing, and a few other things, one's calculation of what is appropriate to pursue is going to be so contextual as to alleviate any concern of undue asceticism or rigidity.
If you approach things the right way, rather than thinking you are Plato plotting out the answer through geometry, or that logic will hand everyone the same answers, then you should have any concern that would spoil your martini!