Umm... Isn't front nine = 240; even if you gutter twice in the 10th...
So he had front 8, nine-miss, double gutter?
X X X X X X X X X --
30 60 90 120 150 180 210 230 240 240
X X X X X 9- X X X X--
30 60 90 119 138 147 177 207 227 237
That's the only way that I can see it.
So the guy never had a shot at 300 if he finished with a 237.