yes, sorry. You are right. It was a misunderstanding from my side yesterday.
Do you use the same master for all coregistered stacks?
By the way, to add elevation and lat/lon rasters can now be done in the interferogram generation step already. Unfortunately, there are many outdated instructions on StaMPS preparation in this forum. This one is the latest I know: Documentation on SNAP-StaMPS workflow
We collected them once in this topic: About the StaMPS category
Please make sure you are referring to the latest version.