As I’ve previously mentioned, Dashboard doesn’t pay attention to the printer’s preheat and fill times. The clock starts running on a print when you tell the printer to print it. My printer lives in my basement, which I only heat to around 60ºF. Even “tented” to capture the air circulating in and around the printer, the printer’s heater can’t “get it up”. I started a small print job last night that Preform said would take 1:41. The printer tried to reach starting temp for about 2 hours before giving up. When I checked it, it was at 30.7ºC vs. a 31ºC target. So I told it to continue. It took an additional hour to get to temp. So the preheat and fill time was longer than the predicted print time. So when the print finally started, Dashboard displayed this:
100% complete with 0 layers printed! Awesome! And then, as the print proceeded, Dashboard counted down from 100% while time remaining increased. So after a few layers had been completed, Dashboard was showing this:
I didn’t stay up all night to watch it, but I did confirm that as new layers were completed the % complete continued to decrease and the time remaining counted up. Presumably time remaining eventually reached the 1:41 predicted by Preform, though I don’t know what happened then because I’d gone to bed. Did it continue to count up, or did it start to count down again? I just don’t know. 
Buggy.