Sorry if I misunderstood, but are you asking about the LCS case? Based on our experience, I would absolutely recommend you continue with the migration procedure. Even if the compaction strategy is the same, the process of anticompaction is incredibly painful. We observed our test cluster running 2.1.11 experiencing a dramatic increase in latency and not responding to nodetool queries over JMX while anticompacting the largest SSTables. This procedure also took several times longer than a standard full repair.
If you absolutely cannot perform the migration procedure, I believe 2.2.x contains the changes to automatically set the RepairedAt flags after a full repair, so you may be able to do a full repair on 2.2.x and then transition directly to incremental without migrating (can someone confirm?)
