This is my 19 year old L3010. The oil line should be somewhere in the window like this when the tractor is level - it makes a big difference - and the 3ph and bucket are down.
The sump in a tractor is pretty big & the level change due to normal hydraulic operation is very wide. As long as it's in the right ballpark you'll be fine. Obviously following the correct check & fill process is best. But as long as it's in the general ballpark you won't hurt anything.
