AutoCAD Print / Plot :: Different Output With Same Page Setup

I have created a bunch of Page Setups (for both Paper and PDF) that work great when plotting from the plot menu. Lately, I've convinced my people to start using the sheet set manager and the publish command. However, on some computers, (not mine) plotting (to PDF) from the Publish dialog box outputs a file that seems to ignore the page setup. Using the very same Page Setup, the file comes out perfectly when plotting from the regular Plot menu. I don't understand how:

1- I get the same result with both methods on my computer (the one used to create all those page setups);
2- I get page setup to apply perfectly on my computer;
3- I get the expected result on the problematic computers when using Plot;
4- But I get different results on the problematic computer when using Publish.

*Note: In the publish dialog box, I use "Publish to: Plotter named in page setup" and then I select the wanted page setup for all my selected layouts in the list. My page setups are using "DWG to PDF.pc3", so the "plotter named in page setup" in all cases should be "DWG to PDF". 

I've been doing tests with PDF files set on A1 format (841mmX594mm) and the output is perfect on my computer. Then on another computer, strangely, I get a PDF with these dimensions: 863.6mmX558.8mm (34"x22"). On the second computer, doing the very same steps, I get 431.8mmX279.4mm (17"x11"). Three computers, three different outputs with three different values. One works, two miss. I'm stoked. 

Keep in mind that all three computers output perfect files when using the standard plotting menu (using the same page setups) so I doubt the page setups are incorrect. Does the Publish command deal differently with page setups than the plot command ? I would have assumed that both commands would react the same. I 'd like my team to be able to batch plot like I can on my computer.