This project urgently needs a "back" button or a way to correct errors. Sometimes when transcribing, spelling or handwriting in a later step reveals the correct form for a previous step. CalBug project site has a "back" button, on programming of very similar format, so it's definitely possible.
If you click on the numbers eg. 6/9 5/9 or whatever a menu of what you have typed in pops up and you can click on whichever you need and go back and edit it. I hope that makes sense?