I see that the payments do match as shown below:
Here is what I did:
1. Took the StackExchange 1 file and pivoted the data as shown below.
2. Joined the above data data with the StackExchange 2 file as shown below. The bottom 3 are calculated joins on the left side.
Note: To be able to arrive at the correct calculated join, I split the pivot field names created in step 1 above by using a comma separator.
Hope this helps.
Test for StackExchange_v2018.2.twbx 104.9 KB