ps (and this should be a rule imho) once you tell us the speed, don't alter it without telling us.
Fair enough, ferris- perhaps get your management to drop EK Flight Ops a note to that effect?
For your info, when we change anything in the FMS profile (an altitude restraint or load a arrival as examples) it does a complete re-calculation of the RTA and may well command a different speed.
We started informing you of the initial RTA speed as a result of management consultation- perhaps either a ruling that once you've announced an RTA speed to BAH or MCT you stick with it, or else communicate any significant changes would be the way to go.