"I'm not sure if I am explaining this well."

I don't think you are.

You say "The first record has 6 days and the second 8 days.". None of the three files you show have records like that. I wondered if you meant "file" instead of "record", but that leaves no mention of the the third file (which is the one with an 8 day time spread).

My best guess is that you should process the files separately (perhaps storing interim data something like '$data_for_file{$file} = [ @wanted_record_data ]') and then extract the records you want after all files have been read.