Using Aggr to calculate percentage, excluding some values

[Den]

My data looks like this:

Date	Machine	Event_Class	Duration	Duration_Percent
1/1/2020	ABC123	Downtime	20
1/1/2020	ABC123	Downtime	15
1/1/2020	ABC123	Uptime	50	0.625
1/1/2020	ABC123	LowPerformance	30	0.375
1/1/2020	XYZ789	Unrelated	25
1/1/2020	XYZ789	Uptime	60	0.4
1/1/2020	XYZ789	LowPerformance	20	0.133
1/1/2020	XYZ789	LowPerformance	30	0.2
1/1/2020	XYZ789	Unavailable	40	0.267
1/2/2020	ABC123	Unrelated	15
1/2/2020	ABC123	Uptime	30	0.3
1/2/2020	ABC123	LowPerformance	20	0.2
1/2/2020	ABC123	LowPerformance	30	0.3
1/2/2020	ABC123	Unavailable	10	0.1
1/2/2020	ABC123	Unavailable	10	0.1

My end result is two different stacked bar graphs that will both be stacked by date and will only display if one machine is selected at a time (I got that part handled by the calculation condition).

The first graph works fine because it is just the sum of the duration of the events on a day, stacked by their "Event_Class":

The second graph I'm having an issue with - I want to see the values of the "Event_Class" stacks in percentages instead of by the values, however, I want to exclude values where Event_Class = 'Downtime' or 'Unrelated' from the denominator of the percentage calculation so that the stacks will always be 100%. I worked around this by doing the percentage calculation of the events in the load script, however I have a new requirement that the user wants to be able to use the alternative dimension selector to change it from the date to the week, month, or year (so using my Duration_Percent column to average it over the amount of days won't work since that number is a percentage of that day's total duration of applicable Event_Class events. Below is what the intended output would look like: