Was looking for the normal sized, pre-measured bottles of Toro oil for my mower because it's easier to just put the entire bottle in without having to check the level, then add small amounts until it's right, or measure out the correct amt. Well, local store was out but they had these smaller bottles which two was about the same volume. We were in a hurry and I didn't read the label closely, just saw 30 and the size. My engine is not a "never change the oil" model, but I was curious if there really is any difference in the formulation vs. the "non-topoff" oil. Same viscosity, SAE30

You're fine using it…I think the only difference is the addition of zinc…sae30 is sae30, you're good to go.

The industry has never really ever gotten this right. In fairness, not all small 4-cycle engines take the same amount of oil but most of the SAE-30 oil sold is used for 4-6.5 HP mowers and the majority of them are within an ounce or two of the same fill amount. I don't recall off hand what that is. I think my 13HP pressure washer takes more. Anyway, though these mower companies don't manufacture the oil they might sell under their brand, it might be smart for them to produce a quantity for the mowers they sell the most of at, say HD or Lowes.

My mower is a never change the oil one, but it is a 2-cycle mower. There is no such thing as a never change the oil 4 cycle mower.