First off, a 529 plan is a trust.  It should be one account holder for one beneficiary. But we have clients who like to use one 529 to pay for the other child's college costs.

But aside from that understand that what can be used for the 529 as qualified expenses goes beyond the 1098-T.  Room and board being the largest cost.  So if you have $10,000 of tuition and $15,000 of 1099-Q you have potential tax on the earnings of the 529 until you enter in the extra qualified costs.  So, go back and get the room and board, the computer costs, etc. and after entering those see what the results are.  Every once in a while you'll have taxable earnings from the 1099-Q but in most cases it ends up being zero.