the BOTTOM LINE,
there are only a few command lines needed, e.g. with 4 reports:
    cat 01.txt | grep Mainten | grep - | awk '{print $4}' | sort | uniq | grep -v ^$ > 01.rpt
  cat 02.txt | grep Mainten | grep - | awk '{print $4}' | sort | uniq | grep -v ^$ > 02.rpt
  cat 03.txt | grep Mainten | grep - | awk '{print $4}' | sort | uniq | grep -v ^$ > 03.rpt
  cat 04.txt | grep Mainten | grep - | awk '{print $4}' | sort | uniq | grep -v ^$ > 04.rpt
    ...
   comm -12 01.rpt 02.rpt | comm -12 - 03.rpt | comm -12 - 04.rpt > common-errors.txt
  cat common-errors.txt (find the ATA number)
  grep -A 16 38-12044 ??.txt
or:           grep -A 16 28-12044 [0-1][0-9].txt (many other options...)
For another script example used for testing:
http://linuxmeister.net/Scripts/Engineering/wx-urls-sh-20jan2010.html
More LINUX info and resources:
    http://linuxmeister.net/Intro-to-Linux/One-Hour-Linux-Sessions-2018.html
http://johnmeister.com/linux     or     http://LinuxMeister.net
 Simply Linux:  https://www.smashwords.com/books/view/705084
 Using BASH on Win 10: https://www.smashwords.com/books/view/703463
 Power Savings of Linux: https://www.smashwords.com/books/view/505731
Windows Suggestions: https://www.smashwords.com/books/view/508267
12 hour Video Course:  The Art of Linux System Administration
 published by O'Reilly Media Study Guide for the LPIC-2 Certification Exams
                           
 thank you....