Huh? I wasn't quite talking about the possible manipulation from verizon.
I was more talking about the auto-adjustment that occurs at the circuit level between the modem and the DSLAM to compensate for noise when a disruption occurs while the two modules are re-negotiating during the sync phase.
(or as drjunky9 phrased it: 'optimized')
Sorry if that was misleading. It was something I coined back in the days when I was troubleshooting service throughput.
Edit: Oh I see, I credited wrong person earlier it seems. whoops.