Applicant asking to use child support as additional income

[Matt Faix]

We have an applicant that wants to use her child support payments as additional income. Without it she does not meet the 3x rule, however with it she does. Her daughter is nearing 18, but she says it is good through her college years. Otherwise she seems like a great tenant (1st impression), we still have to run the background/credit check/references. So who knows, but in the meantime, here are a few questions. 

1. Is there a way to verify the child support end date (we're in PA)? She sent the court ruling, but it does not show an end date anywhere. 

2. Would you still sign her as a tenant knowing that when the child support is gone she will not be able to afford the rent.

3. If so, is it better to do a month-to-month lease in this case. 

Thanks for any help!