To answer the remaining unanswered question, yes, oversampling can help with some dynamics processing.

So the 2x doesn't work on the PC items? Unless they are in an FX chain?

The 2x button toggles oversampling for the plug-ins setup in Aud.ini. It has nothing to do with FX Chains.

Is this a candidate for a feature request? To simply toggle 2x for PC?

I don't think so. The purpose of the 2x button is to affect those plug-ins already configured for oversampling not to setup plug-ins for oversampling. Cakewalk does need to create a tool for managing the settings though. That tool could have a way to create oversampling entries for plug-ins including PC modules. That or at least add something to the PC header to create the oversampling entry. I could add a feature to the tool I wrote to add PC modules but I doubt there is much demand for the original tool. The registry lookup is not that difficult and it is a one-time thing. From there all the action is in Aud.ini and it is not that difficult to maintain.

Excuse me, my bad. I meant a function to toggle upsampling on or off per pc module like the regular vst's.

If it is not to much work I would appreciate that tool a lot.

Manually editing that aud.ini file would mean I would forget and maybe down the road I would like to turn some off again and not realising what I did.

I really want this function. And to be honest all that manually editing is a issue for me. (maybe just mental) but as a non programmer type a guy I am over whelmed by scripts and stuff.

I don't think this is the kind of feature one would constantly tinker with but I could be wrong. Accessing the feature could use some improvement. I have written a tool to make updating individual entries easier. The SONAR Plug-in Upsample Editor is available on the SONAR Resources and Utilities page

I thought that all plugins could be upsampled so prochannel plugins are not being upsampled with 2x

The 2x toggle only affects plug-ins setup in Aud.ini for upsampling. It has no affect on any plug-in, PC or otherwise if they lack an entry in the [PluginUpsampler] section in Aud.ini. By default no plug-in is setup for upsampling. For all but the PC modules, the basic upsample setting may be created by using the Windows menu in the upper-left of the plug-ins UI. Refer to http://www.cakewalk.com/Documentation?product=SONAR&language=3&help=Mixing.26.html for more information.

FWIW the Concrete Limiter is already oversampled internally, so I don't think upsampling for that module would make a significant difference.