Need help calculating the principle balance- bought junior lien

[Derek T.]

So I bought a junior lien and got the payoff and reinstatement amounts. I can't figure out what the principle balance will be if I choose to just reinstate the loan.  Here are the major numbers I'm working with. 

Unpaid Principal Balance:  $652,318.91

Total payoff amount: $816,335.37

Total interest: $98,845.47

Total Amount to Reinstate good through 11/12/2015: $271,256.66

Daily interest accrual: $46.22

Is it safe to say that after I reinstate the loan, the principle balance will be $545,078.71 ($816,335.37-$271,256.66)??

I feel like somehow something doesn't add up.  Why does it state that the unpaid principle balance is $652,318.91, when the note was originally for only $650,000.   Also, why is the reinstatement amount so high, if the total payoff $816,335.37 minus the loan balance $652,318.91 is only $164,016.46.   Do you get a better deal if you pay off the entire amount?  Is it possible that if I reinstate the loan at the $271k, that the principle balance will be still at the $652k?