Did the tire shop give any idea of why the tire failed? Low air pressure, possibly due to cut from road debris, valve or extension failure. We had one issue the second year that we had the MH, checked tires before we left for camp (only 30 miles), next day noticed one flat tire. The road service tech noticed a piece of dirt in the extension letting the air out after I had checked the pressure.
I would not change out the wheels and tires for higher rated ones. There are many c-class MH out there driving thousands on miles on the OEM tires without problems
Beverley & Ken