Tie the top batten in looser.

Changing battens -- stiffer or more flexible -- or shaving battens or whatever you have to do is common practice to get the sail shape you want.

As far as leaving the top batten out entirely, I was kidding, but actually if it is very windy, that is not always a bad thing (sort of like reefing from the top). But that would be a radical alternative for radical conditions.

As far as asking the sailmaker, I assumed you know who the sailmaker is who built the sails for your boat and can e-mail to ask advice. Matt would know.

P.S.
Another thing you could do is put the top batten in backwards, so the soft end is toward the back.

And you already know that usually downhaul makes the top of the leech fall off to leeward. So if downhaul is not doing it, that is what my other suggestions were about.

If you lay your boat on its side and sheet the sail in tight, you can see the effect that downhaul has on the top of the sail, even though you may not be able to see it when you are actually sailing.