Reopening inteviews and interview duration

If I have completed an interview and marked it as complete, but then go back into the interview how does this effect the interview duration. If I was in the interview for 30 minutes before completing does reopening the interview just keep adding to the original 3 minutes, or does the time function start again at 0?

it will show you the time 30 (1st completion) + 3 mins (completion after reopen) = the sum of 2 completions.

Regards,

Survey solutions team support