Can we just start charging the tenants based on historical average usage (by adding a clause to the lease)?

Michael was right about some of the REIAs that charge, but there are others that also charge (for example Alamo REIA) that are actually good!

They always have unexpected 'major' problems arise that will cause the flipper many sleepless nights. 

If I’ve never had vacancy does that mean I’m not charging enough for rent?  

so to be successful at this end of it means.. you need great contacts at your title company that will give you a lot of information and also do a date down literally on the phone with you.. you catch 97% of what needs to be caught but your still taking risk.you need to be able to prep your own docs.. you need to get the seller to a reputable notary  preferably at a title company your going to end up using to resell so they know the deed was not forged or coerced .. then you need CASH to either pay off the loan that day or reinstate it.. you need great relationships with the trustee's handling these you should be on first name basis with the person in charge of the file.. then you need courier service to run the cashiers checks ( in my instance from Portland to Seattle to NW trustee services). 

What is not included and you are charged extra for?

The interest charge is negligible 4.75 and it is tax deductible, for a net effect of 3.5% (assuming 33% tax).  

This is the sum of purchase price plus rehab dollars plus the 6 months house payment money plus a 10% to 20% emergency reserve for unexpected extra rehab costs popping up in the rehab process If you don't even need to use to 10% to 20% emergency fund then the loan reduces at the end and you don't borrow it.Example :  purchase price = 100,000 + 50,000 for rehab and 15,000 for reserve and x months of piti= 165,000 so 3.50 % down is then $ x5775.00HomeStyle is an alternative but on a 2 to 4 unit it is 25% down.

Charge the going rate for a bedroom in your area and put the money you save into an account to buy that 2 family (or something else).

It charges my rentals a management fee, it's income to the management company from which I deduct at the time mainly my medical insurance and co-pays.