It really does not matter what "instruments" ,FCOMS, CAR'S etc have written. It all boils down to what CA(s)A decide to do in the circumstances.
It is not so long ago that CA(s)A supported a Chief Pilot who stated in court that frost could be removed with a bucket and hot water only. Fast taxi would then blow frost off . This on an aircraft of similar size to a dash 8.
The writing does not matter. It is the corrupt application of rules and procedures by CA(s)A and other bullies to suit their own agendas or protect their own positions.
Greedy