Slice N Dice
Grandmaster
It is no so much for me specifically but for others in a general sense. I am fortunate to be in a guild that does champs/RDAs on a daily basis - others don't have this luxury.
The unfortunate part is it doesn't cap out at 3,000,000 like you are suggesting. Which is what the OP is saying - it is lost exp.
I'll try and explain it a different way.
If your meta is level 6 and you hit 3m exp. nothing over that matters unless you have the required taming for it to evolve.
Even if it says 5m, you only have 3m.
If you hit 3m and continue to hunt, and you don't have 116 taming.. you are just farming gold. It doesn't matter what it says.
It is not lost exp, you never had it.
I don't think it's worth bothering the staff to make it not say anything over 3m in stage 6.
But if it's bothering you, be my guest.