Because this part of the city is still filling in, the comparable sales available in Arbor Creek or University Heights specifically can be thinner than in an older, fully built-out neighbourhood, and an agent may need to pull comparables from the wider cluster rather than from the immediate street alone.
New-build pricing in the surrounding area acts as a practical ceiling on resale prices in both neighbourhoods, since a buyer choosing between a builder's current lot and an existing house is comparing the two directly rather than treating the resale market in isolation.
That builder-competition effect is specific to newer areas like these two, and it does not show up in a generic online estimate. Get your hand-reviewed valuation from Joel Dyck.