Hello!
I would not use the default mappings option in BSI TF client. You need all of the mappings as they are in SAP. Same for the tax types as for the tax codes. If you are using the tool for the first time, then check BTXTAXC for the appropriate mappings. Otherwise, these are now maintained in T5UTZC subapplication TMAP.
A lot of issues are happening with clients that have never done table comparisons (T5UTA, T5UTB, T5UTR, T5UTW, T5UTD, T5UTZ) that should have been done with prior application of SAP transports delivered for TUBs.
Hope this helps!
Anna Stevenson
Agrium Inc