I also wanted to see how many loops remained in a running program. However, I used OEM 222. Here is my setup.
1. Make a tiny DRO, about half the size of the G-code button that is next to the Reset button, on the standard 1024 screen. I used MachScreen. There is some space just level with the top of the Reset button, to the right.
2. Click on the DRO after you have it to the right size and place, and a window will open up on the right for setting the parameters.
3. Click on the "Format" line, and the OEM functions open up.
4. Scroll down until you get to "Sub program depth".
5. Double click, and all the info is entered into the window.
6. Edit the format line, dbl click and a new window opens up for formatting the number output. I used; 2 leading digits, 0 trailing digits, Type (radio buttons) double.
The format should now show %2.Of
7. Save file and exit MachScreen.
Run a test program with L10, and the numbers in the new DRO will start at 10, and count down with each pass through the loop.
John