Oliva
The P&W engines are the ones with the high Flight Idle thrust which gives a flatter descent profile that the GE powered aircraft flown at the same IAS. This is why the standard descent speed for the P&W B767 (in Aus) is 320 knots vs 300 knots for the GE B767.
I almost agree with Toecutter in that I do not believe the correct techniques are used when flying at 340 knots until 20 miles. QF training section states that standard procedure during descent is to use VNAV despite several shortcomings with the B767's VNAV programming. If FLCH is used and the aircraft is flown to be slightly low on profile at 20 miles then there is no major drama in slowing the aircraft up and having a stable approach.
The rest of Toecutters post does not deserve a response.