The three main valuation approaches are sales comparable (based on recent sales), income approach (based on the NOI and market cap rate) and cost approach (based on cost to replace/rebuild  the property from scratch).GRM, gross rent multiplier, is the number of years the property would take to pay for itself based on the gross potential rent.

My credit score is mostly good / excellent .Since I’m looking to invest in multiply family properties for rent, my solution is to build an investment group ( if that’s the right term for it) and come up with a much higher down payment or even the entire amount by partnering with investors.

here is the verbiage from the loss sharing agreement http://www.fdic.gov/about/freedom/IndyMacSharedLossAgrmt.pdf First Loss Amount" means the dollar amount equal to the product of (i) 0.20 multiplied by (ii) the aggregate unpaid principal balance of the Shared-Loss Loans as shown on the Loan Schedule attached to the LSA as Attachment A, as updated as of the Closing Date in accordance with Section 2.06 of the LSA, which dollar amount represents the total amount of Losses on Shared-Loss Loans the Purchaser has agreed to realize before the Receiver is required to make payments to the Purchaser with respect to Shared-Loss Loans pursuant to Section 2.l( d) of this Agreement.

Multiplied by 96 units, me and my partner made $1.5M profit on it when we sold it a few years ago.

- Why is gross rent multiplier important?

It is a gross rent multiplier not net ad does not account for debt. 

It's absolutely true that condition and finishes can make dramatic differences in the multiplier.  

This is how much your CF will drop per month.4 - Multiply this number times 12 to give you your CF drop per year.Here comes your answer...5 - Divide the number from Step #2 by the number from Step #4. 

Gross rent multiplier, if I understand it right could give me pretty good value on the building.

If there is an issue on your credit-worthiness side (which, THERE IS if you are hearing "no" from multiple different lenders) then you'd be wise to get that figured out before you spend much more time applying at different places.Be well and an multiply!