You should be able to do a grade scan with GX. It requires that a frequency program list be loaded in order to click Grade Program.
You can do this with the GX using a pulse or with GX's faster scan -- current. Do not use Angle or Angle + Current unless you like garbage in/garbage out scenarios.
Biofeedback is very straight forward when you break it down like this.
All biofeedback scans will scan a set of frequencies. You have 4 modes which consists of two operations -- scan the frequency and optimize the frequency.
No Frequency Program loaded required for the first 2 modes.
1. It will scan ONLY the range defined - a regular biofeedback scan (Single Scan Checked).
2. It will scan the range defined and then it will do a second pass of the frequencies found, to optimize +- 1 Hz of that frequency. (Single Scan Not Checked).
It will take nearly as long to optimize 20 frequencies as it does to scan 3800 frequencies -- so this doubles the time of the default scan range for the Pulse.
A Frequency Program is loaded and required for the next 2 modes.
3. Optimize Scan (Grade Program Unchecked). Scan +- 1 Hz the frequencies loaded and return the best result for each frequency.
As you can see Optimize scan can be isolated if you provide a list ahead of time, otherwise it would have to scan the range first to find what to optimize (Mode #2).
4. Grade Scan (Grade Program Checked). You can change the behavior of the optimize scan to only grade the frequencies loaded. Returns the loaded frequencies ranked from best to worst response. Does not guarantee top frequencies are efficacious or appropriate to the target.