Before revision: However, because speed changes mid-shuttle confuse matters, the algorithm for a change in level is as follows: "the next level commences on completion of the current shuttle when the absolute difference between the time spent at the level and 60 seconds is the least".
After revision: However, because speed changes mid-shuttle confuses matters, the algorithm for a change in level is as follows: "the next level commences on completion of the current shuttle when the absolute difference between the time spent at the level and 60 seconds is the least".