Normally it shouldn't open so many decryption processes at once, but it should wait until the current one is finished. However, the way of determining this is really tricky because the script can't really determine if the decryption is done or not. I can also understand that decrypting can heat up your CPU, but that's because I don't actually own the control about the decrypting process itself. The script depends on Plus!' Log Viewer.exe, whereas other scripts use only JScript or homemade DLLs which the developer has made himself.
As for auto-merging, I understand that there's a huge request for scheduled tasks or automatic actions, but for the moment this is not an easy task. Plus!' scripting system has no specific function to let something happen at an exact moment (e.g. every day at 5 pm) and thus I'd have to use timers instead. But those can have serious complications, e.g. the script may not run at the time the task is planned. And also, I can't think of an easy way to get a GUI for all those possibilities so the user can define what should happen.
I recommend you to do the decryption in smaller parts instead of decrypting them all at once. Log Manager is out of development at the moment, as I'm busy with Countdown Live 2 at the moment. In fact, Log Manager doesn't need to be made with the Plus! Live scripting system, and maybe it would be better if it was a stand-alone application so it could use everything normal programs can. Unfortunately, I don't own the skills to write something in C++ or something. But if I would learn C++ one day, I may want to write a Log Manager which can really manage logs.
/ 
