I'm on 20Mbps and these are my readings:
Cable Modem Downstream
Downstream Lock : Locked
Downstream Channel Id : 31
Downstream Frequency : 443000000 Hz
Downstream Modulation : QAM256
Downstream Symbol Rate : 6952 Ksym/sec
Downstream Interleave Depth : taps12Increment17
Downstream Receive Power Level : 2.9 dBmV
Downstream SNR : 37.5 dB
Cable Modem Upstream
Upstream Lock : Locked
Upstream Channel ID : 4
Upstream Frequency : 45800000 Hz
Upstream Modulation : QAM16
Upstream Symbol Rate : 2560 Ksym/sec
Upstream transmit Power Level : 37.0 dBmV
Upstream Mini-Slot Size : 2
So at 01:00 I'm only getting 5.66 Mb/s on the basis of speedtest.net @ Birmingham (and I'm not bothered). So on this occasion we can't pin it down to your high receive power level - but it needs attenuating anyway.
There's work going on in the network. That much is now clear and that's affecting us both.
Oh - and about that proxy server - you surely aren't gonna continue with that AV method?