Thanks everyone,
You guys were correct. It was that my caller ID was adding the 1 . I was able to verify this through the call logs, as suggested. (The handset on the 110 doesn't have a display, so I couldn't see it there). The other thing I noticed is that I have the "match" value unchecked and it was listed as the 10 digits. My understanding is that it should still be okay as 10 digits is still within the 11 digits shown by the caller ID. Despite that quirk, I've updated my circle and now it is working.