Verifying income on commercial property under contract

Hello all!

I recently begun my due diligence on a 30 unit outside of Binghamton, NY and there are some questions I have regarding the seller's financials. Long story short: the seller is claiming GSI around 240k but only showing 175k and 183k for his 2014 and 2015 Schedule Es. We ran into some issues with the bank over these discrepancies, but it looks like we can deal at 70% LTV.

Furthermore, the seller has provided what seems like a plausible explanation for the missing income, showing how the missing money is "written off" in his management software. So far the seller has been very cooperative providing the necessary documents, etc. 

Given all of this, I know I need to "trust, but verify," so any suggestions on how to handle this is appreciated. The missing income would indicate around a 25% vacancy and his currents are showing a fully occupied property. I'm going to take a trip down there very soon and verify receipts, etc. 

If any of you have any suggestions or need more information please feel free to message me. Thanks for all the help, BP community!