I found a FSBO and am preparing to make an offer. 

Example offer contract from one of my mentorsPurchase Price: $2,000,000Terms: $200,000 cash down Seller to carry a 1st via an All Inclusive Trust Deed on mirror terms with a principal balance of approximately $1,000,000 at 4% annual interest rateSeller to carry a 2nd for balance of approximately $800,000 with an annualized interest rate of 4%, 10 year term, fully amortized, due in full on December 31, 2030Seller to be named on property insurance policy to protect seller's investment

My question to all flippers and rehabbers is what else do I need to factor in when deciding how much to submit an offer?

Current rate is 5.49 Im talking with Quicken Loans about doing a refi, and was presented with the following offers:15 year mortgages- 3.5% with $4900 closing costs or 3.99 w/ $3200 CC30 year mortgages- 4.375 w $3350 CC or 3.99 w 4,820 CCHere are my questions.  

Asking Price: $695kGross Rent: $54645Gross Multiplier: 13.30 (According to MLS)CAP: 5.1%NOI: $36,066 - they didn't factor in vacancy or management and I believe the posted utility cost is lowMy Estimated NOI: $25115$25115/ 0.051=  $492,500Is it unreasonable to offer $492k - $520k?

The of one offer to buy as is which would net about $5-7k.

They also offer 30 year terms with a 7 year balloon. 

Always remember to do the math analysis and try to look at the prospective property before you make an offer or at least have a clause in the sales contract that allows you some time (usually 15 days) and to allow you to back out without a penalty that will not hurt you too much.I also went to college, not that it is mandatory, and I got a business degree that had a real estate emphasis.  

Offer $180.  

Decide what price is best  and offer it to your tenant at that price.