Revo mix and HH Gyro

I was helping a buddy set up his new heli. We were unable to figure
out how to disable and enable the revo mix automatically when
switching between HH mode and standard mode, so we ended up disabling
standard mode.

Later, when I visited the LHS, I asked them if this particular radio
was lacking this functionality. I was directed to a person who was
flying this radio on a helicopter, so I thought I was lucky to get to
talk to someone with real, practical experience. But the answer I got
surprised me greatly:

"There is no need for revo mix at all. They gyro will compensate
automatically, no matter if in HH or standard mode. There is no real
reason a radio should even have a revo mix at all."

I found this very hard to believe, so I gave him a funny face, but he
was extremely persistent, and even claimed he hade tested it himself.

They gyro is a Futaba GY401 and the TX is a Futaba 6EX 2.4GHz.

Is there something I have missed, or was he talking bull****?
-- 
RoRo