Ok, I figured it out:
I noticed in the release notes for Firmware 2.1.5 that “Adjustment Method Options” requires a microSD card installed. My device is hardware version 2.2 which doesn’t have the microSD pre-installed.
Once I’ve installed a microSD card the options are now presented in the UI and working.
Which brings to some thoughts regarding the Zimmerman method… but I’ll investigate a bit more before I post them.