Rinse is a setting on most multiport valves. Your builder may be installing the full flow valve as flow for the spa appears to be the factor driving filter and pump selection. I don't know if the full flow valve option has a rinse position. There is an MPV option for that filter but it would probably restrict flow.

I think your builder is offering a nice filter and you'll be happy with the water quality. Don't worry about the half-ton of sand, you'll never have to replace it (unless you use Baquacil or cellulose DE substitute).