I'm not sure why you're capitalizing all your words here - it's really not necessary.
In any event, every CP for a minor change has a three-year expiration date on it. That recognizes that it often takes a while to go through all of the work required to build out an upgrade, especially at a new site. If it's a leased site, the tower owner will require a structural study to make sure the tower can handle the load, and that's done by specialized firm and takes time.
Antennas and transmitters aren't just off-the-shelf item. They usually have to be ordered from manufacturers and built to spec, which can take weeks or months. You have to have a tower crew to hang the antenna and transmission line. They're often booked out months in advance for big projects. Then there's electrical service to the new transmitter and setting up a STL path, which may require another set of applications and licenses. If it's a directional antenna, you need a surveyor's report certifying it was installed correctly.
Most CPs come with automatic program test authority. Once the equipment is all in place, you can usually just turn it on and start operating. Then you file for a license to cover.
Some projects are built out very quickly. Some take time, for a variety of reasons. Without being part of the project team for this one, I have no way of saying whether it will be a two-month job or a three-year job. And some CPs never even get built out - they're either filed to block someone else from moving, or to provide a plan B in case a rent dispute at an existing site doesn't get resolved.