Don't know where you are but it's still 107 here in Oklahoma daliy. For my area, 10w-30 is a joke.
Again a 10w-30 is not the same, at my house, as SAE 30w. We have over 100 degree temps again like today. A 10w-30 will shear down fast in my weather conditions. All engine manuals say to watch out for oil consumption using multi-grade oils.
Do you store your mower inside? If so, there should reason to use a multi-viscosity oil as viscosity should be selected on operating temperature and not outside air temperature. Being 70 years old I can remember when 10W-30 was rarely used and hard to find. The EPA forced manufacturers to recommend low viscosity oils to slightly improve fuel millage. When low viscosity oils became the EPA forced norm, early valvetrain failure also became common. Vehicles have been redesigned to better handle low viscosity oils. Now the EPA has added small engines to their smog control regs forcing manufacturers to recommend low viscosity oils. Several on this site have commented on the high number of valvetrain failures and that small engines are still built to the old standards to save the cost updating. The Kawasaki FX850V manual does not recommend 10W-30 above 80F, and they make a note that the higher viscosity 20W-50 may reduce oil consumption (engine failure) in higher ambient temperatures. Their chart meets EPA standards but their note is a hint to operators. Good luck and you have a beautiful yard!
I started with 10W-30 in my truck and switched to 30W as recommended by a friend who helped me replace worn rocker arms and push rods. With engine at operating temperature 30W had higher oil pressure at idle than 10W-30. Also 10W30 was only supplying a mist of oil to rocker arms at idle, while 30W would squirt a stream of oil as far as the fender at idle. There is a difference.
Brought to you by Amsoil. You must be some Amsoil reseller. You seem to quote their fabulous wonder literature just fine.