Rear ballast certainly takes weight off the front axle. But do you admit rear ballast also adds weight to the front axle (defined by: it enables you to load the front axle to much more than it would otherwise see)? Which gets us back to the OP's original post.
I think it's hard for people to wrap their head around (or communicate) this contradiction.
3pt balast takes some weight off the front axle when unloaded/lightly loaded....
BUT...
The added lift capacity that ballast gives the loader will likely result in a higher cumulative stress on the front axle as heavy loads can be regularly placed on the loader!
YEs, I understand, and is the same thing I repeat in about every one of these ballast threads come up.
I usually word it something like the followning:
Not only do you need enough ballast to keep the rear down, but you need enough to actually take weight off the front.
Adding ballast increases the load the front can have, up to the point of just enough ballast to keep the rear end down. THAT is the max the front will see. From that point forward, any additional counterweight works to unload the tractor.
Rough example.....3000# tractor with no weight might be able to lift 500# in the FEL then the rears lift....that puts 3500# on the front axle.
Add 500# counterweight and you might now be able to lift 1000# in the FEL before the rears lift. Now the 3000# tractor + 1000# load + 500# ballast = 4500# all on the front axle.
Add a 750# ballast allows you to "just" max out the loader at 1250# and rear tires just on the verge of lifting, so now 3000# + 1250# + 750# = 5000# on the front axle.
Continuing to add ballast from here isnt going to increase lift capacity any further. So lots put a 1500# weight on, 1250# FEL load. The extra 750# works to unload some weight off the tractor. Lets say its countering effect is 500#. So now you have 500# + 1500# = 2000# over the rear, and 3000+ 1250 - 500 counter effect = 3750# over the front.
I usually give some example like that. While unsafe, having no ballast or nothing in the tires is NOT going to overload the front axle. Just not enough tractor weight and lift capacity. If you use counterweight, use enough of it.