Editing an area of a Step-by-Step screencast

Hi there. I'm providing software training and so the bulk of my content is all step by step slides of how to navigate the software. 

There are and will be many occasions in which I will need to edit these slides. Sometimes the edit is just a small correction to a field or section title that needs to be changed. Instead of inserting a new recording slide for that area, can I not just insert the clipping of the new section and merge it into the background over-top the slide? or save that original slide as an image and edit it in an outside tool (Photoshop or wherever) and then just import it back in as the slide itself so it matches the size of the other slides?

I tried the first option of clipping the corrected area and bringing it into the timeline but every time I previewed the slide, the clipping was always off center, even though in edit mode it was fine. 

I also tried the second option where I used Action Fine Tuning and saved the background as an image, then edited it. When I imported the slide as an image, it was off by way of size or position, no matter how much I tweaked it. Therefore the flow from one slide to the next is mismatched. 

Appreciate any assistance.