"Spacing before" is suppressed at the top of the page, assuming that the paragraph doesn't appear at the beginning of a new document or at the beginning of a new section. If the style also includes "Page break before" formatting, the spacing won't be suppressed.

The compatibility option "Suppress Space Before after a hard page or column break" (I'm assuming that's the one you are referring to) controls what happens when there is a manual page or column break present.

When a paragraph with "Spacing after" precedes a paragraph with "Spacing before," the larger of the two values will determine the spacing between the paragraphs.

If you select the "Don't use HTML paragraph auto spacing" compatibility option the two values for spacing will be added instead.

__________________
Stefan Blom
Microsoft Word MVP

Microsoft 365 apps for business
Windows 11 Professional