Vertigo
Just thought i'd add my 10 pence worth
160 till 4 can sometimes be difficult to achieve on the 737-800 due to it being very 'slippy' . I don't know which airport you operate at but we are 'generally' required to be 180 at 7, from there to to ruduce 160 till 4, this generally can only happen by ' gear down, flap 15', which is noisy for the locals. Perhaps a call to the aircraft of ' no less than 160 to 4 miles' would show that there is no room for them to slow further, were as ' 160 to 4 miles ' can ( but i know it shouldn't ) be misunderstood to be a max speed, therfore allowing a reduction .
It seems an easy problem to sove but it's obviously a widely misunderstood. Perhaps a word with the chart markers to add a note highlighting this problem, and a rewording of the speed control policy to leave no open interpretation of this speed rule.