It looks as though the US has a slightly better way of communicating speed control than the UK. In the US you are told to "maintain a speed until advised" this speed is maintained even over frequency changes. On frequency changes the pilot adds "x knots assigned" to his check in. When you are "cleared for the approach" speed is at pilot's discretion unless a speed assignment is restated. This usually works quite well, no misunderstandings.
Having said that we are also being squeezed into the speed control box over here. Companies are requiring earlier stabilisation on the approach. Performance monitoring computers are becoming more common so it is more difficult to "cheat" even just a little. ATC is more frequently assigning speeds and these speeds seem to be required further down the approach. A while back our company reduced the flap speeds on all aircraft by ten knots from the manufacturers speeds to reduce flap fatigue so now it takes longer to slow down. All in all, it is becoming more difficult to meet ATC speed requirements and company (FAA approved) speed requirements at the same time.
Since the real problem is RELATIVE VELOCITY why do we not just use lower speed on all phases of the approch? What is so magic about 180 knots, just change to 160 knots at the same point. It will take longer and use more fuel but at least both pilots and controllers will be happy because the pilots will feel comfortable that they have their approch speed under control and the controllers get no more nasty surprises.
Sorry controllers, I am sitting in the seat watching the runway get bigger sometimes "you gotta do what you gotta do" to get the aeroplane on the ground - with you licence intact!