Running the numbers - How low will they go (banks)

We all know that banks never want to go lower, especially when they just lowered the price. But obviously the longer it is sitting on their books, the lower they will be willing to go.

I've run the numbers on a bank owned priced at 35K (just lowered from 45K), 870 sq/ft (3BR, 2BA). I'm estimating 22K in repairs. We can keep the drywall, plumbing and electrical. Needs some cleaning and paint. No appliances or fixtures. Floors need all redone. Both bathrooms, kitchen need everything (maybe save one bathtub...). Possible furnace replacement (pending inspection - it is old but apparently functional). Windows and siding are actually in good shape. Roof is in good shape. 2 Car detached garage that needs all new siding and windows. Roof is alright.

Comps right now are riding at 80-100K, but because of the declining market I am conservatively estimating 70K final sale price. So 70% ARV puts my max offer at 26K including repairs.

So taking them down another 12K, not going to happen? Maybe let them sit a month? Once I have the offer in, should I just keep looking? Should I make the offer again in a month?