All the answers given above are right on the money! I live in Regents Park, off Trooper so am very familiar with wjat is happening in our area.
The appraiser should not pull comps from 19401, so those prices should not affect you valuation. With the variety of price ranges in 19403 and like one of my collegues mentioned the wide area covered by 19403, the two school districts, the three townships amd more... It would be worth the price of a free phone call to talk to an experienced LOCAL agent to go deeper into details.