Commercial loan advice (office building)

[Cor Bay]

Have a contract on a 10,000 sq ft (main floor) commercial office building with a mix of tenants such as dentists, massage therapists, insurance agent, and real estate company. I know the building well. The seller got a divorce, moved away, and was motivated.

Smaller stable upper Midwest town of 15,000. Good demand for space. The building needs some updates such as a roof (not immediately) common areas such as hallways need paint and carpet. All in all a decent property with an excellent cap rate.

The numbers:

Purchase contract: $325,000

Commercial appraisal (just completed) $450,000

County Assed value: $450,000

Vacant basement renovation costs: $400,000

After basement renovation value via same appraisal: $800,000

The issue is my lender will only finance 70% of the lower of the two numbers either the appraisal price or the purchase price. I definitely prefer to go off of the appraisal. After a short period of time, they will refinance 70% of the appraisal. Seems silly to me. What is the purpose of an appraisal?

Previously I have used local smaller banks, but as I make a move into more commercial I would like to maximize my leverage. We have a great track record and good credit.

My wish list: 80% of appraisal, 20-year amortization, 5+ balloon term.

Any national commercial lenders who will have competitive rates, terms, and fees? What do you normally see on something like this?

Thank you in advance.