Work Schedule - Deducting Lunch Breaks

Hi Guys/Girls

If anyone can help it will be VERY appreciated - The issue i'm struggling with is working out Tea Time, Lunch Breaks & Work carrying over to the next day - I got it to a point where it "mostly" does what it needs to, but its a very barbaric way unfortunately its the only way i knew how to get it to work.

So my question is can you please give tips/advise how can i streamline it.

Breaks are : 10:00 - 10:15 , 13:00 - 13:30 , Day ends 15:45

Please note the sequence of tasks and hours changes often hence me needing the spreadsheet to be dynamic

Btw - D1,D2 etc is which day of the build cycle the task is complete

Attached is a sample of what i created

Thanks