THANKS to both! I would have never figured this one out without knowing about the ship ID. I checked the game in question and my openers are listed higher than the closers present. Does retro-fitting change the ID? When I can retrofit my ships I will put a warp closer and opener in each so I can do both with one ship's command set.
When I have had the luxury of time I have always ordered the openers to move first so as to open on a later day than the closers, as you Alneyan, but at times the loss of even a few days means 45 baseships just escaped my system unscathed after they glassed most of my planets
That seems to be the typical situation right now - every time I just miss nailing a big fleet due to some SM screw up (mostly of my own doing). One thing that helps is I use the "system to avoid" feature to make sure my ships don't go someplace disastrous as a result of my SM screw-ups. Then at least I only waste a movement turn or two instead of losing an entire fleet.
Didn't know that star destroyers may detonate later than day one. With the way my luck has been going mine will pop late and another large fleet will get away. Oh well, some games drag out too long anyway. That's a good thing to know - only now that adds one more thing to have to plan around. If I didn't love this game so much I sure would hate it!
Thanks again.