My question was directed with your bucket on the ground, level indicators are always when your bucket is on the ground. I never said anything different.
To demonstrate my point with your picture.
Look at your first picture, it shows the bucket on the same plane as your tractor, tractor is going up hill. But you want the bucket true level for your operation.
Now lets say you have a bucket indicator that will always show "true level" (that many people think they want) . True bubble level no matter what terrane your tractor is on.
Using your first picture lets imagine what your bucket would look like true level, the bucket would have to be tipped down to go into the pile level. OK
So you scoop the pile and drive away.
Now you come back same hill only this time you want to grade the remaining pile with the hill.
Your indicator shows "true level" you put your bucket on the ground on that hill and your blade will be digging down two inches.
Is that what you wanted to do dig down?
Or did you just want to level the pile smooth with the grade?
That is why indicators do not show true level. Because they would only work in one or two situations and be useless everywhere else.
Most work is done at the grade the tractor is sitting on. The operator has to have some responsibility to operate the bucket in occasions that come up now and then.
You have a joy stick adjust to your needs.
Indicators are just guides to get you somewhat close to what you want. They can always be adjusted by the operator at any time.
Using your first picture if you wanted to grade that pile with the bucket on the ground you would have no problem with the bucket at the same plane as the tractor as shown in your picture. That is how 99% of indicators work, Always level with the plane of the tractor.
You may find some sort of true level digital indicator used on large specialize equipment, but not on normal tractors.
For a true level indicator to work you would only be able to use it on flat level ground. Whereas a level indicator on the plane of the tractor will work everywhere.
IF using your bucket at ground level.
If you wanted to load bails of hay or pick up and load things overhead you would need a self leveling loader which has the capability to aways adjust the bucket level
no matter what height.
But even the self leveling loader will not work in your pictures on a hill. The bucket is level at any height but with the grade of the tractor.
Does anyone see my point why you can't have a true level indicator?