Actually the
only reason to have to 'slow up', RB, would be if structural damage was suspected and then you WOULD in any case need the gear to get down reasonably quickly. I cannot imagine what IAS/Mach you have been cruising around at at high level............
At 37,000ft the 200 would have an IAS of around 230kts or less. Not until around 30,000ft is 270kts even a consideration.