Tuning ATSC Sub-Channels on Mini

I have noticed that when attempting to tune sub-channels on my mini, the - button on the peanut remote does not seem to have any effect. My mini is fed by a Roamio OTA, and the peanut remote for that DVR can be tuned using the - button. In other words, if I enter 10-1, that station is tuned. If I try the same task with the mini, pressing the - button enters a 1 instead, so if I pressed 10 and then the - button, 101 would be entered instead of 10-1.

Is there a setting to fix this, and has this issue been noted by other Roamio OTA/TiVo Mini users?