If the bank is not looking at whether the space is vacant or not, why would they look closely at what the rental price is if payments are being made?

* All loans are priced based on the paper rental price, among other things. Pretty much no one buys commercial property with cash, so if the rent is lower the next purchaser won't be able to get as big of a loan, and the original landowner will be underwater.

* Posted rents are sticky, in that they are the basis of the negotiation for the next round of rents, and especially so for commercial real estate where leases are multiple years long and landlords often throw in renovation for leasees. Banks would prefer a space be empty rather than lower rent and then you have to negotiate from a lower base, and getting another tenant would mean having to rip out everything you put in for the current tenant at your own cost.

You see similar issues in multifamily where landlords would rather offer you "X free weeks" instead of lowering the actual rent by an equivalent amount.