Well, even I cant answer that based on those numbers solely because I play fog and dont keep track if people get bonus....
but I would guess that its 98% certain that bonus doesnt mean too much, compared to the dice, and compared to where the people drop.
All I can say is this is instinct after playing many after the final update, but on 1v1, it is a random as hell map. Hardly ever do I see the drop affect the game, more than the playing/dice affect the outcome.
So far as I can tell, and have seen, you can win from any spot on the map, given certain circumstances. Again, the bonus is helpful, but I do not think its a deciding factor, and honestly, it happens so infrequently, especially compared to other maps, that I certainly dont worry about it.
Its a great 1v1 map, and possibly the most fair on the site. Sure, it still has an advantage of going first, but its much easier to counter than on nearly any other map, especially on fog. Id have to play it another 200 times to really suggest any change whatsoever I think.
Id say pass it. If its skewed now, it just gives the map a little character in my opinion. Find one more player to confirm this though maybe.
Oh, and above 20% Id guess is absolutely probable. I didnt even realize the proportion was so low. Id say going first affects it far more than that bonus. Again, double check.