Writer changes my paper format

[mplsmom]

I am trying to create a custom paper format in my document. I am changing the User format to be a half sheet, 5.5" by 8". I already have this set up in my printer. Writer keeps changing it to Big 32 Kai, 5.51" x 7.99", and it causes problems because I have an old document that I want to reuse in part that is formatted as 5.5"x8" and it messes up those pages. I would prefer to just copy and paste and not have to go back and adjust the format on those pages.

My question is primarily why does Writer keep changing my document, and what can I do to stop this?

[EarnestAl]

@mplsmom

old document that I want to reuse in part that is formatted as 5.5"x8" and it messes up those pages.

A difference of one hundredth of an inch (0.25 mm) messes up formatting? Expand/reduce the margins in the pages by that much.
I suspect a missing font might be the issue. Check the font box, if the font name is shown in italics then a substitute font is being used. Either install the original font or find one with the same metrics.

A home printer will have slight variations in the track each piece of paper takes and printed inkjet content/air moisture will cause variations in paper size. the search terms dimensional stability of letter paper suggest a larger potential variation than 0.01"

I suspect significant digits rounding it to the nearest size.
If I enter 13.97 cm x 21.59 cm (or 5.5" x 8") I get Big 32 Kai.
But if I select User and enter 139.7 mm x 215.9 mm then the page remains at that size

LibreOffice 7.3.1.3 accepts 5.5" x 8" without change. LibreOffice 7.6.7.2 changes that to Big 32 Kai.