I just started to use Publisher and find that leading is very odd, actually, uncontrollable. This has nothing to do with paragraph spacing, leading override or any of the clever things. It is just basic leading or line feed, the space between baselines. It makes no difference whether this is specified in the style sheet editor, the paragraph context editor or the text context editor. The default is set solid, if I add fixed amounts 12/13 12/14 or percentages up to 110% nothing at all happens to the leading. If I specify a three point lead 12/15 or a 120% line feed then the paragraph goes to 12/24 or double spaced.
There might be some sort other context that is new to me and this software might work in a different way but I cannot believe that this, as a problem, is what it appears. Serif would be vilified and everyone would know about it. But I am no novice in typography. I trained old-school and have been to every type of school since for more than fifty years so this granddad does not need to be shown how egg sucking should be done. Even so, I am missing something, obviously. The point is illustrated in the attachments. The first is set 12/12 the second 12/14 the third 12/15