I have quite an experience with ericsson RBS series especially 2202 and 2206.Timeslot sync problem can be linked to a malfuntioning of the DXU.
6+6+6 Configuration can be achieved in both RBS 2202 and 2206 using CDU-C+( HYBRID couplers will be required to combine the TX paths.CDU-D is a filter combiner.CDU-G and CDU-F are used in RBS 2206.