Need help to Calculate TAT and KPI with two rules

[prem407]

Need help to Calculate TAT and KPI for the below mentioned two rules

1) Completion of work by EOD if received work order before noon time
2) completion of work by next business day if received work order after noon time
3) also need to minus issue raised (issue mail sent time and resolution received time) between received and completion time.

I will be very thank full if guide me to calculate my TAT & KPI with reference to above conditions

 

[vletm]

Interesting ...
1) TAT ... https://en.wikipedia.org/wiki/Tat
2) KPI ... https://en.wikipedia.org/wiki/Performance_indicator
3) EOD ... https://en.wiktionary.org/wiki/EOD
and so on ...
You, prem407, need all just without any sample file?