I've just gone onto sky fibre on the up to 38/39 Meg package. I was told I'd get a speed of a minimum of 34 Meg. On the routers homepage it's connecting at 39999 Meg, that seems to be rock solid. When I do a speed test it varies from 21-27 Meg. Is this normal? Should it fluctuate like that and should I be expecting the 34 Meg?