Help on number(hours) divide calculations

Hi everyone (again)

Hoping someone can point me in the right direction regarding Numbers(hrs) and dividing, sample workbook contains drop down lists, Machines run for 8 hrs a day unless breakdowns and other factors anyway the easy part is column E downtime is calculated on Column D straight forward divide calculation, works well for a single row but is it possible to have a formula that see's the Machine name that had 2 jobs run in the 8 hours so therefor it needs to split the 8 hours 4 ways on 2 rows, see sample

Hope thats understandable lol

Thanks