clock in , clock out and absence issue

Hi friends,

In our company, planned working time is 7:00 to 16:00.

I have an approved hourly absence request from 8:00 to 10:00, but instead of 8:00, I'm going to leave company at 8:20.

So my time events are as below:

clock in = 7:00

clock out = 8:20 (instead of 8:00)

clock in = 10:00

clock out = 16:00

approved absence request = 8:00 to 10:00

my expectation from system:

delimit my absence from 8:20 to 10:00.

Which customization are necessary in which table or PCR or Schema?

please note that:

More than 1000 employee are working in our company ,so control and correction wrong data manually by HR Administrator is very difficult, inexact and time consumer, so I want this process to  be done automatically by system.

I really appreciate any help you can provide.

Best Regards,

Leila