Update on the problem, with more information.
It happens every time. I chose double-sided sleeve. I think a CD insert is around 4.75 H x 4.75 W inches.
When I print on my HP psc 1350 printer, the label prints at about 5.75 H x 4.875 W inches.
This is totally frustrating me. If nobody knows the solution in this forum, I guess I should try customer service? I haven't tried that yet, since this forum has given me all the answers to any questions I have had so far.