Lysefjord exploit?

[Eagle Pursuit]

I just discovered that Lysefjord will award your unit a promotion after each time you upgrade it. Previously, I had believed it would only do it once.

So:
Get a promotion on your Galley
Upgrade to Caravel and get another
Upgrade to Ironclad and get another
Upgrade to Destroyer and your unit has reached the final promotion.

Obviously, you get there faster if you're unit is doing some fighting along the way.