IRM read permission does not allow to change a filter or a pivot, nor to run a macro
The RMS permissions on a document for a user depend on the permission a user has for that library or document in sharepoint. The mapping from the sharepoint permissions to the RMS permissions are fixed and cannot be configured at this moment. This causes problems for users having sharepoint read access, when opening an excel workbook because they cannot change filters, make or change pivots, running macros. This makes the reading process of RMS protected workbooks unusable.
Maarten Kerckenaere commented