I cut a 6" dessert cake into 6 plated portions, I don't use someone else's chart. I definitely am a heavy server, I'm also in the mid-west!! So often people tell me everyone went back for seconds........and I love to be generous. Even if you cut a 6" cake into 8ths, it's still not so easy getting people to pay $9.38 per person. Whatever, I'd like to get as much as I can per cake too........but I'd rather have the reputation of being generous and reasonable then tight and expensive, that's my personal business choice.
"The customer might go with whoever says they can give them more servings or presented it so that it sounded like they were paying less per serving, even if it was for the same size cake."
I think most customers choose a cake based on who's going to make the best tasting and looking cake they can afford. If you come in at a reasonable price for a delicious cake that looks great, people don't bother to shop any further. It's only when they are shocked by a quote that they question things and begin to compare prices. Ultimately I price special occasion cakes on the amount of time it will take me to make it and decorate it. My time is more expensive then flour, butter and sugar. So I'm reasonable on my base pricing, but my pricing rises by how much time it will take me to complete it.