I have a shelf full of left over synthetic oils bought for different hydros over the years
Strait mineral oils are no problems because they can be added to to each other but synthetics can react adversely with each other so they sit on the shelf ready to top up the hydros that almost never need topping up .
Remember the $ 40 is our monopoly money but still is a 1/2 hour labour
The Toro oil is even more expensive & funny enough no one stocks it except in the oil change kits with $ 50 filters