How I would do it in RB -
Import your audio and Chords
Select a blank track (important!)

Go to Chords view and select the bar before you want to insert a new one
Right-Click Copy it (just that bar using the From-Thru settings in the popup) and make sure the Chord Symbol & Events check boxes are checked
Right-Click Paste that, making sure 'Create Gap on Selected track' is chosen and use the From section in that same popup to define the next measure as where to paste it.

Click OK
Now you have a new chord sheet with an new measure that you can alter as you like & no audio was disturbed

Do the same thing for any other measures needed.
After that you can generate or whatever as needed.

Last edited by rharv; 5 hours ago.
I do not work here, but the benefits are still awesome
Make your sound your own!