Ok, so I assume the bulk mock up is for anyone that does not want to use the bulk listing tool (where the mock-ups are part of the process). Essentially it is for those that want good mock-ups but list to Etsy manually or want to post to other sites like shopify.
What I want to achieve is this:
I want to change small design details on some posters and update the mock-up images on Etsy without deleting the whole listing and starting again (I did this to a lot of my listings recently due to a trademark infringement so became paranoid about the smallest details that could make it happen again so changed 40 images but deleted and reposted them. But what also happened was that I completely messed up any SEO and traction that I'd got for my favourited designs, so they have completely tanked since. Things are now picking up again but I realise I probably did it the wrong way and could have kept my actual listings in place but just changed the images, but was not sure how to go about it, so deleted them from Etsy and my PS files and re-loaded again through the bulk listing tool which ate a lot of my credits but also I ruined my best viewed posters traction and results (as the reloads were assinged new titles, tags etc). Essentially starting from scratch.
So my question is, can I use the bulk mock up tool to make a change to the mock up elements of each listing only (to swap out the original images and load up new ones in their place without doing any damage to the listing stats and views etc). Hope that makes sense! Maybe it is not possible, but would like to find out what others do?