I use the Redding Comp seating die also and do like it but I had trouble with mine at first.
It has a feature where you can set the zero to your most common seating depth you use, then you can record the + or - micrometer number for any other bullet you want to try. This will give you a record to go by if you decide to record the settings for each type of bullet you use.
I keep track to a certain extent.
But, my OALs started growing while I was loading and it turned out an adjustment screw inside it was unscrewing while I was using it, changing my OAL a little on every so many rounds. Some blue locktite fixed it. I was disappointed that I had to take it apart to do this after just paying $103.00 for it, but it's been really good ever since.
You also have to watch the setting on it while your loading , the mic only has an o-ring for friction and my mic would unscrew when loading a lot at one time.
After using it for several years I do think their 9mm Comp Seating die is worth the extra money because their seating stem seems to fit all the 9mm bullets I use, and they are all seated straight.
After that the Micrometer is just a bonus.