NNN - does this insurance amount sound reasonable?

[Carrie Kearns]

I own an office building (I used to practice in it but have since sold the practice and the new owner is leasing the building from me) with a NNN lease. I believe my lease says I pay for the roof and parking lot. He opted to pay the insurance himself instead of reimbursing me (he sent me proof of coverage and I am currently working for him part time). Obviously I need to pay insurance for my part but I'm not sure my insurance agent understands NNN - my insurance for my part was ~$1800 for the year. The building most recently appraised for $300K. Any thoughts if I'm overpaying? Prior to the sale I was the leaser and the leasee. Thanks for you thoughts!