Got the 8 off fairly quickly but took me a bit to find a different path that was even close. Very interesting idea and it's tough for me to understand exactly why it's faster.
8 off and out of idea... *edited* Years later: At 648 got 6 off. At 649, 2 off and won at 651! Unbelievable board. Glad to be done. To my eyes, a 9 points.
Somehow, I managed from 8 to 6, then quite quickly to 2 off. Now NO IDEA, again. What a terrific level! Kept me on the verge of despair, even at 8 off! Will rate it when I solve. Edit: Yessssss. I'm ashamed to say, it took me cca 600 tries. But I DID it! :)) 10 stars!
Wow the path is really interesting and amazing, just didn't think that it can be done like this before, even got a 2-off for once just before getting the correct path.