I have a Bush Hog M2561 ZTR that comes with 20W50 dino oil in the hydro system. I am changing the hydro oil filter (100hrs.) and thinking of changing out the oil to 15W50 Mobil1. The service dept. at the Bush Hog factory even told me it would be a good thing to do. That being said, my question is. Will there be any noticeable performance increase in the operation of the hydro system?