how are you determining that the child is paying over 50% of his support?
Fair share of rent? Fair share of utilities? Fair share of medical expenses / medical insurance premiums? food? clothing? schooling? does all that add up to more than 50% of what it takes to support him?
if the child isn't on your return, you wouldn't receive the $500 for him, but the broader question is whether you should be claiming the child. Normally the test for support is based on expenses not based on income.
