30 vs 28 days for subscriptions

Maybe I’m a dying breed here, but I still consume 2000kcal/powder on a daily basis. This presents a (1st world I realize) logistical challenge. In olden times the monthly subscription hit every 28 days which makes sense if you consume a box every 7 days. It also adds some regularity to the day of the week the stuff arrives (assuming processing orders returns to something more predictable… which it seems to be). But a few years(?) ago they switched to 30/15 days. This means more often than I’d prefer, I’m logging in to switch the ship date a few days. Would it be so terribly difficult to add 14 and 28 to the 15/30/60 day subscription options?