Attenuation jump with BT Voyager 2110

Nine days ago, I migrated aways from a fixed 512K service from Demon to ADSL Max from Madasafish.

I ordered a BT Voyager 2110 router from Madasafish when I signed up but it didn't arrive until day 3, so I ran with my old Netgear DG834v2 up until the new router arrived.

As soon as I plugged in the new router, the line attenuation shot up from 58db to 63db and the speed dropped from 2176Kbps to 1600Kbps. Consequently, I decided to put the Netgear back in (after switching off for half an hour) and the usual figures returned.

This morning (day 7), I checked the figures again (the router had been on for a couple of days by this time) and was shocked to find that the speed had dropped to 1600Kbps (attenuation was still 28db). The SNR was at 10 (it used to hover around 7).

I have read:

"When a user upgrades to ADSL Max the system will attempt to synchronise the user modem/router and the BT exchange DSLAM to determine the maximum stable rate (MSR). ADSL Max is rate adaptive - the BT system will record upper and lower line rates. Data will be collected for a MINIMUM of 10 DAYS before the lower line rate is rounded down and to become the MSR."

So I'm wondering... Is my Netgear showing 1600 as a result of the moment of madness with the BT Voyager or has my Netgear just been letting me down slowly? Is this normal behaviour for a Voyager 2110?

Thanks

Doug