Unexpected attribute value definitions in 19.505 style:page-usage

We currently have:
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19.505 style:page-usage
The style:page-usage attribute specifies the type of pages that a page master should
generate.
The defined values for the style:page-usage attribute are:
● all: if there are no <style:header-left> or <style:footer-left> elements, the
header and footer content is the same for left and right pages.
● left: <style:header-left> or <style:footer-left> elements are ignored.
● mirrored: if there are no <style:header-left> or <style:footer-left> elements,
the header and footer content is the same for left and right pages.
● right: <style:header-left> or <style:footer-left> elements are ignored.
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While this may be correct, I find it strange that (all == mirrored) and (left == right). Is this really intended? For example I would have expected that mirrored would switch the left and right regions of the headers on the left page, but that isn't specified here.