Mobile Home Park Analysis - Offer Price

[Bobby C.]

Hello all,
I am one email away from offering on my first MHP. I would like to run my numbers by you people who are much smarter and have more experience than I, so I don’t make a fool of myself.

The property is 32 units at $500,000, all park owned homes, quoted cap 10/12%:
Units: 32
Stated Rent: $266 per unit - $102,144 Gross Income
Expenses stated (2013): $40,266
NOI: $56,206

I have found several discrepancies in these numbers, deleted some and added or changed several such as property taxes, which were much higher than stated.
My numbers are as follows:

Gross Income- $102,144
GOI: $92,951 – Average vacancy in area is 9%
Expenses: $57,954
NOI $34,997 – 7% cap
Offer price, as I was quoted 10.12% Cap: $350,000

Will this make sense to the agent and owner as to how I arrived at this offer price? I want the property as cheap as possible, but I do not want to insult the owner so much as he will not negotiate further with me. This isn’t the only property I am looking at, but the best one I have found for value add opportunity and market.
Please let me know if I am not clear enough, or making any mistakes in my calculations!!!