Shell Programming and Scripting

The number of arrays you're using isn't your problem. The problem is that the search criteria used to select your start and end points are selecting a start time where field 12 is 0 and an end time where field 12 is 2. You either need to ignore field 12 when saving and subtracting values (i.e., stop using t_arr[$12] and just use something like saved_start_time) or relax your criteria so you select a start and a stop time from each set of lines with the same value in field 12.

If you want to output multiple timestamps, there is nothing in your current script to tie a start time and end time pair of lines in your output to a particular elapsed time printed at the end of your report. (And, if you have more than one start and stop with a given value in the 12th field, you will print start and end lines for each pair, but the elapsed time will only be for the last end for that value of field 12 - the last start for that value of field 12.) None of your outputs indicate which value of field 12 is involved, so trying to tie them together manually won't be easy either.

Help us helping you by indicating in your sample which lines belong to a single event that you want to time. If any single event can be identified, its start and end time can be isolated, and the time difference calculated.
In order to get at what you showed in your last post, try setting all $12 fields (= index to your arrays) to the same value; then the delta will be printed.