Because most of Willowgrove's housing stock is a similar age, price differences there usually come down to lot position, finished square footage and whether a basement was developed with a permit, rather than to decade-by-decade variation the way an older neighbourhood shows.
New construction is still active around Willowgrove, and a builder's price on a comparable new lot can act as a ceiling on what a resale home nearby is worth, since a buyer choosing between new and resale is comparing the two directly.
That builder-versus-resale comparison rarely shows up in an automated online estimate. Get your hand-reviewed valuation from Joel Dyck.