How could they know that? They might know the day the ballots were picked up, but the time they were turned in? There is no time stamp at these ballot collection boxes.
It is possible ballots were segregated by the box they were turned in.
When boxes are first processed, they are put into a sorting machine which notes the date and time that it began and completed plus the location the ballots were received. Each step of the ballot process is put onto the internet so that voters can see where their ballot is at any given step of the process. The ballots of the individuals Andrews claimed to have submitted were not found to have been submitted in a different way from his account. Had they been, you can be assured that Dinesh’s distributor would have used it and publicized it.