Version 1.12 added the replacement template feature for ground formations, but it seems to be missing a functionality that I personally would want it to be used for.
What I would like to have in particular would be a button I could press to order the construction of only the unit elements that the formation is missing compared to its selected replacement template. So for example, if you have a formation with 500 soldiers, 50 tanks, and an HQ, and it's missing 100 soldiers and 10 tanks (compared to the replacement template), then I would want to specifically only construct these 100 soldiers and 10 tanks that are missing (instead of ordering the construction of a new full formation, which would make me end up with a superfluous HQ and more units).
In my current game I have a formation where I later decided to make a couple changes to it by adding additional unit elements to it. I was hoping I could use the replacement template feature to order the construction of these newly added elements, but that doesn't seem to be possible. The alternative would be to build an entirely new formation and to mark that one as a replacement formation for the original one, but that wouldn't really make sense, because I would still end up with one formation that is missing the units anyway.
My only options seem to be to either very micro intensively create a new formation type which contains only the missing units and then to use that as a replacement formation or to just build a new formation and to delete the old one, both of which don't sound like satisfying options.
If anyone knows better ways to handle this kinda thing, let me know.