I think that I found where the problem is. In the table [Financial_combined] the same CaseID can be several times and sometimes there are lines cancelling themselves. I need to tweak the measure so it still counts the nr of distinc ID, but for this particular one (Payment&NoFee) when the SUM of the payments is >0 and the SUM of the Fees is 0 or blank
You have to modify the filtering in the CALCULATETABLE then. Right now we are just filtering for amount > 0 and that is why the row > 0 is taken into account. You want SUM(amount) > 0 as we do working out the second listing.
For this to work well, all IDs with payment in 'Financials' would need to be in 'Fees' (either with or without payment). That seems not to be the case. The missing ones will not be removed by the EXCEPT.
A safer, less restrictive option is to go with INTERSECT: