Well, the reason is that there is no explicit "Increase Size" preferences panel. All the adjusters of that panel are included in the "main" template, that is the file,
https://github.com/chrispetsos/prefsEditors/blob/master/src/pmt/html/PMTUIOptions.html
What i've tried to do is make this a subcomponent in PMT. My effort is here,
https://github.com/chrispetsos/prefsEditors/blob/master/src/pmt/js/PMT.js#L117-L225
I have, sort of, succeeded in making the extra adjusters switch model bound. The more/less label now has a "for" checkbox bound to it for which i react on changes by updating the subcomponents model. I also listen for modelChanged events and perform the sliding events accordingly. The thing i don't like here is that i have to manually update the model with that requestChange() call, which is also DOM dependent. Thought that this would be done somehow automagically with that wiring of model, selectors and protoTree, as in normal adjusters.