Power Query Enter multiple overlapping ranges

Sorry not very good title, I've always done this in excel but would like to know if someone can suggest a pq method,

I have a time column in 5 min increment and have to enter the number of people on shifts with those time so

10 = 08:30 - 12:00 , 8 = 09: 00 = 11:00 , 5 = 10:00 - 11:30

to do this I usually go to options and allow interaction in 'Formulas' and also 'manual update' so a to control when it happens,

then insert a helper column to enter the shifts and a result column next to it so in 'result' I would enter = helper + result

then as I enter the shifts in helper F9 to carry across, each time deleting as I go and enter the new shift , at the end copy paste values junk helper.

But is there a way to do this in Power query? I have attached the workbook with a sample of the above, iterate in manual update

Richard.