Probably not... That statement being true, there is definitely an issue with image statistics being a little confused in that area. I think we decided we were supposed to change the label to "ISO" for DSLRs and that got dropped... your binning is obviously 1x1 so it's not super useful (unless we extend software binning into sequence images...). Anyhow, that defect aside (we will fix that), Ideal Exposure time is a function of:
- Actual exposure time for the camera image
- Mean background ADU
- Gain (e- / ADU) for that binning (1x1 for you)
- Readout noise (in e-)
Binning does not affect this calculation. If one of those pieces of data was missing, you would see NA for that field.
True, we do not attempt to calculate ideal exposure time for images taken in the past.