Oldhat: Fairly unusual to get such dramatic drops in throughput on a cabinet.
Could you also post a tracert result from wxc.net.nz as that would be the speedtest server you are using.
I disagree.. I pretty much never had peak hour lag until I was cabnetised. Now I get sweet connect speeds but on nights where things are congested it's a nightmare. Not sure if its cabinet backhaul, or Chorus <-> TC Handoff but something in there causes nasty lag.