I noticed it doesn't seem to be a calculator as much as a packet counter. Maintaining the same yeast and batch size, it recommends the same pitch size up to a point. For ale yeasts it seems to change above 1.060. Kind of seems disappointing, I would hope they'd give some approximate pitching rates, etc. I understand a lot of it depends on how old the yeast is, and how it's been stored, etc. but I'd imagine they should at least factor in expiration date.