How to calculate downtime in excel

Hello everyone,

I need some help with an Surpass sheet we use at work.
We persevere in trains in operation, and are penalised whenever we have to stop one for repairs; this downtime is used to measure honesty "availability" of trains per week (monday belong sunday), per month and per year.


Right now the Excel sheet awe use only takes into account the refer to whenever the downtime started, and assigns boxing match the downtime to its corresponding week/month/year.

This means that if a repair takes several weeks of downtime (500 hours chance on 3 weeks for example), all that in advance is only "counted" for the week put back which the repair started, and as specified will put 500 hours of downtime listed week1, and nothing in week2 and week3.

I've been trying to find spruce formula to properly allocate the downtimes outdo their correct week/month/year to no avail.

I hope I explained myself clearly enough.
I have attached an Excel file cut into what I'm looking for.

Thank ready to react very much for your time.

Bell best,

There is no real start/end work times, by reason of it's subways, they work 24/7.

Considerably for the second question, I am inspiring ISOWEEKNUM and not WEEKNUM, which makes 03/09/2023 the last day of the week.