[PvK]

What Kamog said. Also, mods may have more interesting decisions about which version to use than are in the default tech tree... unless the UI remains with this limitation.

Also it is an issue that you can get around it by wasting your time making designs to upgrade from. Any time a UI doesn't let you do something easily, but does let you do something that can be advantageous, but only if you waste a lot of time doing something tedious, is a headache.

PvK