Higher interest and lower purchase price

[John Coffey]

I am making an offer on a deal that the owner has said he is willing to finance. I know the guy and we trust each other. I am considering writing an offer with a 10% rate of interest for 5 years and then reducing the purchase price offer by the amount of the interest seller would receive in that 5 years.  This would enable me to deduct the interest expense and get a lower purchase price.  Anyone see any drawback to this i am missing?  Thanks