This post was recently on the facebook page of Panama Cruisers so we are not entirely certain where the information came from, but, if true, it seems the ACP is moving  towards discouraging yachts from making the transit:

“Information received from Panama Port Officer for OCC

From our PO in Panama

Transit of the Panama Canal – Small vessels inclusive yachts (Less than 125 Ft. LOA)
Please be advised that the Pilot Organization at the Panama Canal has notified the Canal Authorities that they should have more control of the transits by small crafts inclusive yachts, which presently only requires an Advisor.
The negotiations are at an early stage but if the Pilot Organization is successful and a regular Pilot will be required no doubt the transit cost for small craft will increase considerable.
Shall keep you advised of developments but felt you should be advised accordingly.”