Yes, that's how the import times are held. Basically, the import start time is the export finish time. As soon as the export finished, the import starts.

The variable $scheduled_export_days tells, how many different import / export are stored. It can be max 7, 1 for each day. If its value is e.g 5, than there are export reports for the last 5 days. I need it, because I have to write GUI-Monitor, which displays the last 7 days and the fitting import / export report for each day.

I hope this information helps you out!