the address I show on the 1040V for my TX client is the PO Box in NC, but maybe the program updated it at some point in the past 6 weeks?

Ive found that payments always go to a actual address, not just IRS with a city and zipcode.

Thank you. 

Are you sure you are looking at address for 1040 with payment?  It hasn't changed here:

https://www.irs.gov/filing/where-to-file-addresses-for-taxpayers-and-tax-professionals-filing-form-1... 

And did the IRS/lockbox people actually return the check?

Thank you.