You are correct. A xb21 250will run 80 with a piss poor setup with pretty muchwhatever you want in the boat. 90 is a number that can be achieved with a good setup and conditions any time of the year. 95+ is reserved for great conditions cool weather a great setup and the desire that do it. I also don't prefer to run over 90 without a buddy nearby.
Strokers are a a touch faster yet and bullets a touch slower.