Common sense?
Levelling off at 5450ft in the vicinity of the airport to comply with a speed request is unlikely to make you friends with ATC. On the approach? Independent parallel approaches use different platform heights for obvious reasons so I'd be inclined to stick to it like glue to ensure separation.
On the other hand, if I'm already level at 3000ft on the localiser, decelerating nicely, and ATC offer a further descent to 2500ft and further with the ILS my inclination would be to remain level and intercept the glideslope from 3000ft in the spirit of our CDFA policy. Others might pay lip service and start a 200fpm descent towards 2500ft.