I have noticed that Wavelab and Cubase do not seem to look at 64-bit processing plugins the same way… just curious why the difference?
For example, one of the free plugins I use is called GClip.
Wavelab → File → Preferences → Plugins → Show 64-bit float plugins → Gclip is listed here. In the info window within Gclip, it shows version 1.2, build 1.2.4.4, win64, 13 May 2015
Cubase → Studio → VST Plugin Manager → Show plugins that support 64-bit processing → Gclip disappears from the list in Cubase when “show plugins that support 64-bit processing” is checked. In the info window within Gclip, it shows version 1.2, build 1.2.4.4, win64, 13 May 2015
AFAIK 64 bit audio output is only supported by VST3 plugins. This is a VST2 plugin, so while it may be able to process audio in 64 bit, the output would be 32 bit.