I should know this, but....

Is it OK to run the WEc1 calcs with the same landscaped area (in square feet), but with different plantings in the baseline and design cases? In other words if the owner's baseline case assumes 100% turf grass, but the design case calls for 50% turf grass with the remaining 50% as drought tolerant grass that does not require permanent irrigation, is this approach valid? It seems to me it would be, but some members of the team have differing opinions.

Thanks
Brian