The space between two paragraphs is the GREATER of
- the "space after" on the preceding paragraph and
- the 'space before" on the second paragraph

In your screen captures, I believe a complicating factor is the Double line spacing. Is that case, the text has to sit 'somewhere' in a double space, does it sit at the top, middle or bottom of that 'double space'? Whatever the answer is, this will have an effect on the spacing to adjoining paragraphs which aren't also set to Double spacing.

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Andrew Lockton
Chrysalis Design, Melbourne Australia