I have a new Quest that I am using for its first mowing season. I wanted a second set of mulch blades so I could sharpen and rotate them out on a regular basis. I purchased my second set of blades from my dealer about 4 weeks ago and it is a newly designed blade from Exmark. They do not mulch nearly as well as the older design. I a, experiencing clumping tbat I never experienced with the older designed blades.