The autofill routine seems to have its issues. I'm not sure how waze limits the results based on proximity, but as you have found it is not perfect. Waze states that some improvement are coming in 3.9 and 4.0.
Regional Coordinator: Mid-Altantic, US
Verizon, Droid Turbo, Android 4.4.4, Waze 220.127.116.11