The B&S SAE 30 is pretty stout oil. It’s good for 100 hours or yearly, whichever comes first.
Since 10W-30 and SAE 30 have the same viscosity grade at operating temperature, so there won't be any problems. The 10W-30 is a better oil since I do my last mowing in November when the temperatures are much cooler. I want the cold weather protection as well as the warm weather protection.I'd watch the oil consumption on that thin 10w-30 Amsoil. She's only a thin 10 grade dressed up with magic to play like a 30w at 212F. Can't beat some good ol' SAE 30w.