Appraisal Adjustments - only $5k per bedroom???

[Jay Levy]

I'm currently in the process of refinancing a 2 family house which has two 4 bedroom 3 bath units in it.  There are a shortage of multifamily comps in my area and the comps that were used are all 2 bedroom 1 bath two family properties.  The appraiser has decided to use the unit value approach.  We can't use income approach as part of the income is Short Term Vacation rental and the appraiser / bank won't accept that.  With that said the properties typically rent for $800 a bedroom a month, so the bedroom count has a direct impact on the value since in off season its college rentals.

The issue I'm running into is the for the additional 4 bedrooms the appraiser is only giving me $20,000 in adjustments for, though the average per bedroom price of the comps is $175k.

Has anyone had any success in making a case the additional bedrooms should be valued at more than $5000 a bedroom?

For some additional content the property is worth somewhere around $950k - $1.1m.

Thank you for your thoughts and advice.