After a season on the north american continent i no longer see any need to accelerate past 250 below ten , going up or down, unless specifically requested. Climbing at high speed , cruising at high speed and descending at high speed use more fuel,(particularly in V/S)than they make up in time saved.According to my observations that is.
It does increase your chance of missing someone in a Fecked up situation, either an errant intruder or an unsure vistor to cas. If its good for that reason in uncas then its good for cas. Cant see any advantage to speeding up.