A little more info.
Phone: Samsung Galaxy Note 3 running Android 4.3 (stock, not rooted)
Slingbox: Slingbox 500
Video Source: Directv HR24 connected via component cables.
SlingPlayer app: Slingplayer for Phone Android Version 2.7.1
Issue: No way to punch in channel numbers that include a "-".
Should be able to duplicate this 100% of the time. Support duplicated it when I called them. They also confirmed that it works on their iPhone app. So it's just a bug with the Android phone app.