10-30 vs 10-40 oil

[HikerToo_imp]

Hot summer I am running 20/50 synthetic Motul

Hot summer I am running 20/50 synthetic Motul
User manual only gives 10/30 as approved.
I heard the service manual says 10/30 and 10/40 when temps are really hot.
20/50 could allow start-up wear on your engine, which I've heard is where 80% of all engine wear occurs, when you first start the engine and the oil has not had time to circulate.
So, good luck with the 20/50 which can be used on a 20 year old lawn mower to fill in the crude tolerances.