Hi @Roberto,
Glad to hear that worked well for you. 
Please don’t forget to mark the post that answered your question as Solution via the … (3 dots)
The inactive relationships are required because there can be only one active relationship between two tables BUT both Start- and Enddate are- and should be treated equally in these DAX calculations.
@sam.mckay showcases how to deal with that in what’s know as the orders in progress pattern
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Furthermore @BrianJ brought some video’s together in this post on TREATAS and USERELATIONSHIP
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I’m confident that after reviewing these you’ll have a better understanding on how this works.