Although the difference is small, aparently it makes a difference when I merge a cover made in Word and the score made in Dorico (unless this happens for another reason).
Is there a reason for this difference?
And is it the same in Dorico 6?
In any case, I tried to changed it manually, making a custom size.
However, when I am exporting PDF, it doesn’t allow me to change the page setup from A4 to custom.
I can’t answer your first question, although the difference in size shown by your two page images is much larger than the 0.5mm difference between the nominal dimensions (210mm vs 209.55mm). It looks to me like the first page is letter and the second is A4, as in this image, which I just made from a letter page and an A4 page:
As for the second issue, when you export a PDF from Dorico, it will always be exactly at the page size defined in Layout Options. You are not able to change this, which is why that Page Setup field is grayed out. (I agree that it’s confusing for it to show a different size.)
Here are the files: Word A4 in Word and PDF, Dorico A4 in Dorico and PDF, and both PDF combined.
I noticed one thing however: in Word, if you print to PDF both with Adobe PDF or Microsoft Print to PDF, it gives you the same size. However, if you save it as PDF, it gives you a slighter smaller page, the same size as Dorico’s.
That is probably the solution, but anyway the files are there to be sure.
