There is another link in this forum for dot commands. You can check how much time remains on town buildings and autoguns. At ports and v bases you only have to check the time remaining on Autoguns. You need to make sure all autoguns are down before releasing troops.
As already mentioned in this post, I have delivered troops to a map room and 2 or 3 did not get in. I returned with a jeep and made the capture. I believe the troops already in the maproom are good for 15 minutes.
GL