Fixed Unit Releases?

[LordDeadwood]

What is it that determines when fixed units are released? Beyond the "scheduled" time? I have some units that have the asterisk next to them in the release dialog box, which I understand means they were not released at their scheduled time. Fine. But then there are a couple of question marks in the listing instead of a percentage. Is there a parameter that controls it, or what? 

Also, there seems to be a limit to the number of times per turn that I can target a particular hex with indirect fire. After I've hit it 3 or 4 times, that hex is never again "lit up" as a target for any indirect fire unit, regardless of spotters or range or anything. This is the first time I've noticed this. Again, I looked for a parameter of some sort but didn't see it. Inquiring minds want to know...