The RYA's unpublished recommended 'trial number' has been 948 (based on extremely limited info) for the past couple of years when I have enquired.
So it is not really suprising to see 950 is now there published 'experimantal' number as there must have been barely any new data from last year.
My recommendation would be for latest version 05 boats to continue offering the class recomended 930 (based on data and inituition by PhilA) to PROs. The boats are very capable at that and it will help you get to heaven.