If the overhead is directly related to the rental and that's the only activity of the corporation, I believe it may be appropriate to reflect those expenses as part of the rental activity. More info would be needed about the OH what it is, and why it is incurred.
Also, in my opinion, an S-Corp (or C-Corp) is the worst way to hold rental real estate. The issue is tax basis. With any other type of entity, your share of the mortgage debt would be part of your tax basis. Not so with an S-corp. Your basis is your equity contributions and direct loans by you to the corp though they too can generate problems + income - losses - certain tax credits - distributions. Mortgage debt does not count, even if personally guaranteed
