Yes, the 6100/9200 are 8PSK units as is the 6000U.
Yes, you can change modulation on a per TP basis.
Dish does that now with QPSK for SD and 8PSK for their HD with a mixture of MPEG2 and MPEG4.
But the MPEG is not mixed on a transponder either.
They would still need to swap out all the 6000 units to an 8PSK capable unit PLUS all the commercial gear in the SRDU side of things.
That won't happen very quickly and by that time it's so near the MPEG4 swap or the point will be moot if the churn escalates as predicted and their HD base doesn't justify it or the business will be up for sale again and all projects on hold.
Teachers needs to fix it or FCKU it.
Keep in mind that not everybody's native tongue is English, so expect grammar mistakes, it doesn't makes them any less intelligent, it's just a bit more confusing to read the first time through.