[Vegas Street Rider]

I have my GZ in the shop to have some new tires mounted and the owner/mechanic (Suzuki certified) and I were discussing the heat here in Las Vegas. I told him I ran 20/50 viscosity oil in my GZ during the summer months to protect the engine in the plus 100 degree temps we incur. He said he uses a 50/50 blend of 10/40 and 20/50 which essentially gives him a 10/50 range. Does this sound right? I was always told not to mix different viscosities. Would like to hear from someone learned on the subject.