I read this in the owners manual:

Always use Honda ATF-Z1 (Automatic
Transmission Fluid). If it is
not available, you may use a
DEXRON transmission fluid as a temporary
replacement. However, continued
use can affect shift quality. Have
the transmission drained and
refilled with Honda ATF- Z1
as soon as it is convenient.
To thoroughly flush the transmission,
the technician should drain and refill
it with Honda ATF-Z1 (Automatic
Transmission Fluid), then drive
the vehicle a short distance. Do this
three times. Then drain and refill
the transmission a final time.

Is this what we are supposed to do everytime we replace the fluid or is just the process to follow if we have used Dexron as a temporary replacement?

I have just been draining the old fluid, cleaning the drain bolt magnet, replacing the crush washer and then refilling with new fluid every 20,000-25,000 miles, rather than the 120K miles as suggested on the maintenance schedule.