I have a some of doubts about your flow. In the stored quarterly files you are using the association between the Excel file and the Quarter Selection. Are you filling that association somewhere before going to the page?
Instead of doing that probably you need to send the Quarter Selection as page parameter, wrap the excel data widget with a data view that use that page parameter and set the xpath like this:
I'm still not getting the object inside the xpath :
Normally, I don't know where to fill the association, I have already a populated entity ExcelFileDocument and I cerated one called QuarterlySelection that is populated on this page :
The variable is not known
Here as you can see :
Because you using Datagrid and xpath is call on page you can access to your object via token '[%CurrentObject%]' but still you will not be able to filter it with attribute of currentobject, instead of using xpath you should use microflow as your Data source.