Traffic is... has it right there. If there is just one spike of traffic into a sector or airfield, and giving a couple of "Take off Not Before" times will just spread that loading, then it saves putting on a flow restriction and possibly giving everyone a slot. IT can just ensure that the traffic is a little more spaced. Only the same as putting on an MDI or miles in trail procedure, but for a sector further down the line. It's rarely just one aircraft, usually a couple from different places due to arrive somewhere at the same time.
If the aircraft is then ready sooner and nagging then give FMP a call, the picture may have changed and it might not be an issue any longer.
Cheers,
N
xx
"Keep smiling, it makes people wonder what you're up to..."