In all honesty when you're dealing with financial stuff, you want to draw your info from "Real Data" and minimize on the assumptions. Especially if you're basing your decision possibly on a "false positive"
Realtor derived info is current, from a huge data pool and more accurate than any other source. So why use 2nd rate information when you can easily access the best source.
How come you're not inclined to ask Realtors? Bad experience? Also, find an "investment specialized realtor" because pulling up the last 3 months of solds may not be the best data to draw from depending on what you're game plan of action is. I used to instruct my realtor on the criteria because I knew more about investing than they did.
If you have serious issues about "asking a realtor", there may be bigger "unrecognized" issues lurking in the dark.