I think it's pretty tough to read the wording on that quote any other way. You cannot move out of the grid. Whatever your movement is, you always stay in it.
If you're at the 3/10 spot and have a move up, you cannot, and must stay where you are. If you're on 0/5 and move down, you stay put. If you're on the left edge at 3/0 and get a diagonal up/left move, you move straight up to 6/0.
I think you move what you can. In your example of moving diagonally up 4, if after 2 moves you hit the left edge, I think you still continue the final 2 moves up, just not the left part any more. Losing the final 2 moves would be too much punishment.
Yes, I think this occasionally means that you gain or lose slightly more or less than you should mathematically. I'm guessing that they found this easier than trying to explain re-positioning your markers elsewhere.
And perhaps the game design/strategy takes this into account.
If you're at the 3/10 spot and have a move up, you cannot, and must stay where you are. If you're on 0/5 and move down, you stay put. If you're on the left edge at 3/0 and get a diagonal up/left move, you move straight up to 6/0.
I think you move what you can. In your example of moving diagonally up 4, if after 2 moves you hit the left edge, I think you still continue the final 2 moves up, just not the left part any more. Losing the final 2 moves would be too much punishment.
Yes, I think this occasionally means that you gain or lose slightly more or less than you should mathematically. I'm guessing that they found this easier than trying to explain re-positioning your markers elsewhere.
And perhaps the game design/strategy takes this into account.