Measure totals (common problem but cannot solve)

Data sharing is unfortunately not possible. I can clarify this taking couple of steps back.

I have two fact tables which are used for EBITDA:

-Invoicing table (columns: client, employee, date, invoicing value) -> data on a monthly basis

-Cost table (columns: client, employee, date, costvalue) -> data on a monthly basis

EBITDA calculation is a simple DAX measure [Invoicing value] - [Cost value]. As you can see this is per client per employee per month due to data granularity.

-> I want to get dynamic list of clients which are EBITDA >= 0 and other list for client which are EBITDA <0 during the WHOLE time period chosen by user on the dashboard time slicer. If person chooses the timeline to be 1.10.2017-1.6.2018 then I would like to have each client's total EBITDA of that period (9 months).  

Example: A client's EBITDA for each month during 9-month period is Oct: -1 Nov: -1 Dec: -1 Jan: -1 Feb -1 Mar: +1 Apr: +1 May +1 Jun: +1 -> Total of -1. That would mean that client would be on list "EBITDA <0". And the total value of -1 would occur for that client for each month (selected). That way it would not count individual positive months but take a look only at the period total.

Did this clarify the wanted outcome?