Calculate total hours if time ranges overlap

Here is the modified spreadsheet and a word doc explaining the logic

Hi MikeNDavis,

Thank-you for your quick response to my thread and apologies that it has taken me so long to reply. The spreadsheet you worked on for me re: overlapping downtime hours is working great and I'm very grateful for your help.

The only issue I am currently having is when there are 4 or more pieces of equipment down over the same time period, the overlapped time is calculated more than once. In the attached spreadsheet I have highlighted where this occurs. I have been trying to figure out how this can be fixed but so far I'm not having any luck. I believe it may be able to be fixed by adjusting the Earliest Usable STD formula but other than that I haven't got a clue. If you get a chance would you be able to have a look and give me some advice as to how to solve this?

Thanks and kind regards,

JL_Stewart