Hi, can't help with tyre wear on the michelins but I have 315 Toyo Proxes rears on staggered 20" BMW rims, I've done 11K miles since buying the X with these tyres fitted & so far the tyres are wearing evenly.
As suggested by others, pics would suggest over-inflation. ( I run mine at recommended 32psi ) although I always check them as last time it was in for some work my local garage said they were under-inflated & he'd corrected them for me FOC, when I checked them he had inflated them to 40psi !! I'll aks him not to bother next time.
Phil.