I updated the firmware on my DUAL GPS 150 to V4.2.4 and using the Bluetooth GPS mode on TA, the screen says 5 Hz!
So Congratulations to Weston & team on an application that has met the goal: 5 Hz updates.
I still can't see the data sentences coming through on the screen tho, unless someone knows how to do that. :) The DUAL GPS Status app doesn't show that stuff, unless you count the little dot near the top that blinks quickly.