The formula is different. For each game you award each player this value: his score in that game / winner's score of that game.
You then just compute average of these values for each player (it will be never above 100%).
Andrethegiant
251 251 100.00%
255 255 100.00%
259 259 100.00%
182 182 100.00%
242 271 89.30%
191 236 80.93%
240 288 83.33%
93.37%
petki
188 188 100.00%
275 275 100.00%
150 150 100.00%
251 251 100.00%
211 251 84.06%
183 255 71.76%
182 236 77.12%
90.42%
DiddleySquat
189 189 100.00%
271 271 100.00%
310 310 100.00%
236 236 100.00%
260 288 90.28%
193 275 70.18%
134 188 71.28%
90.25%
Congratulations Andrethegiant, you will be promoted.