That makes no sense to me. He must be a very very junior soldier for that amount.
The military has their own child support rates for each rank. That amount would apply to a private or a corporal. If he is higher than that, you should be getting more.
You can call the CSEA and ask for a ‘change of circumstance review’. You will submit your income, he will submit his and they will determine the correct amount.
My story has to do with a wife getting pregnant immediately after the wedding, and then seeking divorce immediately after the birth.
If the wife initiated the divorce specifically for the child support, she should bear the responsibility. IMO
However, in cases of the Husband walking out, or drugs, or violence, or infidelity, then that is a whole different situation and I would support the wife in those cases.
Go back and re-read—my SON joined the USAF in August after he turned 18. I did not have to support him, although I helped him a lot during his years at the USAFA. Nothing from his father.