First off, all feats preformed by Prime or PC heroes/villains, are lame. They're legit feats, I'm not claiming otherwise, I'm not saying they didn't happen, they're just lame. But seriously, that's not what we were discussing because everyone already knows that they are ridiculous in terms of power-set and feats.
People are trying to claim that non-PC/Prime Superman can lift 1 billion tons... not true, not even close! and if it is true, all I'm asking is for you to show me the scan and stop using speculative logic.
Anyhow, I didn't make up the rules; take it up with the handbooks who say, a character has to lift the weight above their head and extend their arms... whatever weight they can do this with, is their strength level.
As far as towing anything in space... moving objects in freefall is not that impressive. The only part of the moon feat for Superman, WW and GL that was impressive, is knocking/pulling it out of orbit... that takes roughly, one billion ton of force. Moving the object through space isn't impressive for a Class 100 because out of orbit, there's nothing holding the body in place. Basically, once it's out of orbit, it's gonna move on it's own, all they really did is guide it. It's like putting a car in neutral and pulling into the desired direction... hardly a billion ton feat.
Same thing applies to Superboy prime... except he probably could actually lift a billion tons given how outrageous prime is.