As I suspect you're already aware, one cannot call Commands via ObjectDBX.
However, as you might also already know, you can quickly iterate the PlotConfigurations Collection, to Delete() them:
- (defun _DeletePlotConfigurations (doc) (vlax-for x (vla-get-plotconfigurations doc) (vl-catch-all-apply 'vla-delete (list x)) ))
You can copy the ACAD_PLOTSETTINGS Dictionary entries from one Document to another, in order to 'import' named Page Setups.
As for setting a given named Page Setup as active for one or more Layouts, that will require something like this:
Cheers | 
置顶卡
