Perhaps, although I'm not sure there are many stats from non-Broadcom modems available to check.
In any case, I think the IFTN equipment is still better than the TSTC equipment.
Edit: I just spotted some stats from what is presumably a Technicolor 585v8 (Infineon chip), ADSL2, showing the usual 18 dBm DS output power, and showing the IFTN vendor code. So perhaps it is the combination of modem and exchange vendors.