The strike price can follow the declining principal balance.

If you factor in principal payments in the equation, I'd be looking at $338/mo as of right now.On the flip side, I'm pretty sure on a conservative estimate, we could sell our home at 175k, possibly as much 185k.

My reasoning is that I like having a lower required monthly payment in order to maximize my monthly cash-flow.Remember, you can always reduce your principal balance at any time with a HELOC (or an loan for that matter) simply by making a, "principal reduction" payment.

Your DTI is based on the cost of homeownership of the property, including:1) principal & interest 2) property taxes3) hazard/homeowners ins. 4) mortgage ins. 5) secondary/other financing6) condo/HOA feesOn a multiunit property, you can use 70% if the rental income from the other units, assuming you don’t have a 2+ year history of rental income on your tax returns.

It keeps trudging along and we've managed to get the principal from 114,400 to 92k, so no complaints there.

If your managing your own properties that you have a clear ownership interest in .. no licesne requiredif your managing properties for your clients IE collecting rent.. negoatiating leases etc.. then yes you need a brokers license with a PM component.. and you would have to work for a broker for 2 years then sit for your principal broker exam pass that and the property manager component..does not matter resi or commercial.. reason is your handling lots of money for investors and or negotiating contracts state wants those folks to be licensed and accountable. 

If you buy 5 houses with $100k down and borrowing $400k on each at 5% for 30 years  you will pay $30k P&I $6k principal and $24k interest per each house and $20 k cash

There are many ways to calculate return and some formulas do not include all recurring costs while others include principal reduction and other such unrealized gains.

Net Worth of the borrower principals combined need to equal the loan amount and the liquidity needs to be equal to or greater than 9 months of debt service.  

Pay off principal?