We recently upgraded a test system from S/4 1610 to S/4 1709 and one of the interesting things that we found was that SAP is recommending that the switch for activating profit center accounting in Controlling should be activated. This was a bit of a surprise because I found no mention of this in the Simplification document for 1709 or in any on-line searches.
Ever since release ECC 5.0 clients using the new general ledger with the profit center or segment scenarios active were warned against activation of classic PCA. With the new GL scenarios profit center functionality was incorporated in the GL and the old profit center ledger 8A was not activated. In this case the classic reports in the information system for PCA would not return any results if they were executed.