I have a problem in my pick loop

Here's my story: In Meditech, Ctrl F7 deletes the previous word, so I wanted to make a pick loop using Ctrl F7 so I could delete more than one word quickly.

I made this command:
{command}{Ctrl F7}{PickList}back1{PickList}{NoSpacing}

Here is my Pick List entry:
{command}{Ctrl F7}{NoSpacing} Short: back1. Display: Back one word

My short is aa to start the ball rolling.

The first time I use aa; it will delete the previous word, and "back one word" appears in the advisory, so I ; again, and the word before that is deleted. However, at this point nothing appears in the advisory so I can't use the ; again for a loop and if I want to continue, I will have to type aa again. What am I doing wrong?