Yes, SOMETIMES there is a difference in rates available between Business and Liesure when using a corporate code. Unfortunately, I've even seen availability differ, so watch what you have set in your profile and searching for rooms. Most times I find cheaper rates available using other search criteria. I've changed my profile to show no preference for smoking or beds just to get a better hit on the search. Then change the search criteria before doing the booking and noting my desires in the comments.

Searching on SPG.com is a time-consuming chore.