How to calculate Average Handling Time using Excel formula

Hello everyone,

Hope you are having a great week.

I am trying to figure out a way to calculate AHT (Average Handling time) for each cases irrespective of the dates. Just to summarize the table, DE stands for Data Entry. Average handling time is calculated as the total time taken to complete a specific case (for instance, AHT for Case 1 is 3.27 hrs). In situations where a specific case extends to the next day or if additional tasks comes in between Data Entry (e.g. Case 2, 4, 5, 6, 7 ,9 in the below table), there has to be a formula to calculate the AHTs in such cases. I have attached the excel sheet for reference.

Can anybody help me calculate AHT for the below table?

Thanks in advance.