An amount sent via email in a spreadsheet, 2 days after the date we agreed I would receive payment, was equal to 12% of the net profits...Vastly different from the 60% split I was anticipating after rehabbing, managing and selling the property...This calculation included doubled the closing costs, recouping revenue and expenses that were already subtracted from the HUD/CD.

I can't answer your first question without doing an in depth market analysis.Your second question, you take the sold comps and subtract your budget for rehab and buy, and if the result is at least equal to your desired budget, that's a profitable property. 

All these homes will sell it within a price range subtract the repair cost from the market range is what you anticipate to get.

You should have a clear means to add or subtract people.

This is the other exit for your money.4 - Take the Cost to Enter and subtract it from the Exit Comp of choice. 

Would I also want to subtract HML and closing costs?

They look at how much your property will appraise for, subtract 20% because they want your to still have equity, then subtract your mortgage balance.

I thought with ordinary businesses you can subtract expenses from revenue and pay tax on the end result allowing you to keep reinvesting into the business? 

@Stef Martin if your intent is to scrape and rebuild, then you need to use comps that are new construction in the area to back into a value on the land by subtracting all of the costs to do the deal including your profit.

We first subtract 70% from the price of what the price of the home would be if it were completely renovated, then we subtract the cost of any repairs.