ahhhhhhh seems about normal. my guys also fluctuate about that much.
Any more then 5 % of the body weight, is means for concern if there is no real reason(fledging)
I would reduce the amount given at night, but keep it up till he refuses. It prob wont be much longer. Sydney was about 9 months when he stopped(he was just getting a few tastes at night)........He was just enjoyin his mommy birdy time. But thats just me. I am not a breeder. just a mom.