Windward boat/proper course

You can't go reading your assumptions that a leeward boat sailing through wind-shadow will necessarily be sailing above her proper course into somebody else's scenario.

OP said:

... After falling into my windshadow several times they heat it up a bit and luff slowly but surely onto the heading they should have been on in the first place  ...  the 29er was not luffing above her proper course, ... it was just that her proper course was a much higher heading than mine.

I'm tootling along down a broad reach minding my own business. A 29er with kite up tries to overtake me to leeward (big mistake), coming from clear behind me. After falling into my windshadow several times they heat it up a bit and luff slowly but surely onto the heading they should have been on in the first place (sailing a higher and faster course). As I'm alongside them I have to luff up above the heading for the mark. I want to head straight for the mark but the 29er wants to head above it and then gybe back to it later down the reach.

Now, there is no sudden luffing by the 29er and I have plenty of time to keep clear. The question is, should I have to? I think I know a boat coming from behind and getting an overlap to leeward cannot then luff above his proper course. However, the 29er was not luffing above her proper course, it was just that her proper course was a much higher heading than mine.