[NTG-context] A5 != 210mm x 148mm ?

Hi, If A5 is 210mm x 148mm (and the internet assures me that it is https://papersizes.io/a/a5), then shouldn't these two setuppapersize variants give the same result? They don't *seem* to. %\setuppapersize[A5] \setuppapersize[height=210mm, width=148mm] \starttext \input ward.tex \stoptext The reason I ask is because I'd like to prepare a PDF for printing via IngramSpark, and have discovered that (bizarrely) their Australian branch doesn't support A5 for colour books. They do offer 6x9 (229x152), and I was wondering what values to use in 'setuppapersize', so I thought I'd experiment with the A5 sizing because it's a well known size. Now I have no idea :-( Thanks Kerry