Can you upgrade the weapons AND the construction-arm at the same time? Or, do you have to choose which path to take? (Example: Amazing firepower with T1 build skill, or amazing build speed with low firepower....ect)
Your commander has three slot categories. You can not have a fully combat ready Commander that is also great at building things. Each slot can only have one path chosen but if you wish to revert back to original form you can do that also.