I see it all the time with all types of equipment. My theory is that for said engine brand new only has assembly lube in it and might take 6.2 quarters of oil to get exactly on the full mark. Now you’ll never get that 6.2 out the drain hole in the pan unless you tear it down just all these little spots the pool oil. So what I’m saying is that said engine/gearbox is engineered to hold 6.2 and the manuals state that but during servicing you can only drain 6.0.