Going back in quiz, to end of slide?

I am working in Adobe Captivate 8 with the finishing touches of a e-learning course. The client wants back and forward navigation. But I'm not able to get everything working.

I've made both open question (Text Entry Boxes) slides and slides with video that they don't have a 'forward' button on the beginning of the slide. In the slides with video the user has to wait 60 seconds until the 'forward' button appears, and in the open question slides the user has to answer a question to make the 'forward' button appear.

The problem is that when the user uses the 'back' button the user doesn't enter the end of the slide:

- The user has to wait 60 seconds (again) to be able to continue.

- The user has to re-submit the answer the the open question.

Is there a way when going 'back' that Captivate enters the end of the slide? When the user has already waited 60 seconds or answered the question?