Ask HN: New telemarketing strategy?

I've gotten several phone calls from telemarketers today. I noticed a curious relationship between the time of day and phone number:

Time -- Phone Number

10:25am -- XXX-XXX-1025

2:49pm -- XXX-XXX-1449

4:45pm -- XXX-XXX-1645

Is this some new trick where you can manipulate the caller ID to just show the current time in 24 hour format instead of the real last four digits? Or maybe they're just automated systems that call at the time of their last four digits because whoever wrote the schedule was feeling particularly lazy?

For some further speculation, the area code is the same as the one on my number. If I had to guess I'd say they're spoofing through some shady VOIP service?