i have the same issue. I use four digit IDs like 1000, 1200,1450, 2000 etc. So i assumed that i would not need the additional step you describe. But Npriting creates Tabs in the Excel in no specific order starting at 1450, 1715, 1200 and so on.
I am not sure how to implement the step you mentioned: "Then you can set your page/level by the region order field and label it as the region name."
I was wondering how you labelled your Page as the Region Name as opposed to the Region Number. I have a similar use case so I created an ordering field but when I add the Page to excel I don't seem to be able to label the individual tabs anything other than their Order Number. I am on NPrinting April 2020.