A false/continuous/sacrificial fence only (generally) works on a partial profile cut.? On a full profile cut, the outfeed needs to be offset the same as the depth of cut.?
You would need a stepped board, or a shim/packing attached to the outfeed.? There is a method of partially feeding a board into the planer, where the DOC on the board matches the depth of the shaper cut, resulting in the step needed for the continuous fence.?
In practice the outboard fence is faster, unless you have a lot of different widths for the stock being?used.