It is not possible to add images in existing projects. Some time we want to add 2-3 more images of same area…but we have to create a new project. so if you add this feature it is of great help.
It is not possible to add images to another existing project because step 1. Initial Processing calibrates and adjusts all the images together.
If you add some images, the reconstructed model needs to be computed again since at the moment the software does not allow local adjustment. Actually even few images might bring significantly useful new information to the project so that they will not have a local impact but reprocessing the entire project is necessary to get the most optimal results.
Your workflow, creating a new project, is what we would recommend. It requires some manual work indeed, but since it is needed to re-process step 1 again, it should not be much longer.