ARV Confusion

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I'm having a little difficulty estimating the ARV on a short sale. I have 2 recently sold comps for the subject property. Here's the breakdown:

Comp 1:
Sold Price:$189,900
DOM:61
Square Footage: 2067
Year Built: 1961
4 bedrooms
2.5 bathrooms
Date Sold: 2/2011

Comp 2:
Sold Price: $185,000
DOM: 29
Square Footage: 2070
Year Built: 1961
4 bedrooms
2.5 bathrooms
Date Sold: 12/2010

Subject Property:
Accepted Offer at $65,000
Repair Estimate: Finding out Monday
Square Footage: 1797
Year Built: 1961
3 bedrooms
2.5 bathrooms

All are the same style. I was advised to calculate the ARV based on price per square feet. When I did this, I came up with an ARV of $162,846.33. Basically, I averaged the 2 home sales and divided this average ($187,450) by the average SF (2068.50). The price per SF came to 90.62, and I used this value and multiplied it with 1797 (subject property's SF). My concern is this: Is it really appropriate to knock off $24,603.67 from the subject property's value because of 1 less bedroom and a smaller SF?

Thanks in advance for your replies.