Pricing when lease option *decreases* for commercial RE

[David Pugh]

HI All - I'm considering a post office purchase. The early year cap rate looks good, but there are problems in the out years. The tenant has three five-year options on the lease that are $16k lower than the first three years on the NNN lease.

I'm curious how folks think the property should be valued. I thought about offering $240k less ($16k * 15 years) than the asking price. But of course, the rent is still totally flat for 15 years, so I'm not sure how to factor that in. 

How do you value a property when rents go down in the future lease options? If the price is low enough, then the math might still work. 

LMK what you think. 

Dave