the footprint of the tier determines the amount of servings so whether the individual tier is 3inches tall or 5 inches tall you get the same number of servings.
pans can come in different depths so it just depends on which you prefer as a baker as to which set you purchase
has nothing to do necessarily with the layers you create
i think there's more than one way to price a tier cake.
- by the number of servings is one way
- by the profile of the cake is another way
for a hex cake that needs to feed 100 plus top tier i would explain that in this case they are buying a profile
not purchasing according to amount of servings.
i'd charge them for all servings involved for whatever set of hex pans i bought--it's a 4 tier set
some are in 2 inch increments and wilton is in 3 inch increments--but they buy all the servings in this case to get the profile, the hex shape they want
if i hand cut the hex cakes so they get the exact number of servings i would bust the price out so that the regular pan sizes would be cheaper anyhow
that's how i do it