A Commander can conduct or direct a FOR RECORD APFT TEST be conducted as often as they wish. If only 2 FOR RECORD TESTS are conducted in a year the test must be separated by at least 4 months. See AR 350-1 for specifics.
However, the Commander also has a duty and responsibility to ensure that the FOR RECORD tests are not conducted in a manner that is unsafe, unreasonably place the Soldier at risk of injury, or are of a frequency that undermine unit mission/readiness or Army Standards.
If you are asking how long a Commander must wait to implement another FOR Record APFT test if a test was started but could not be completed or was canceled… then there is no regulatory answer for this question.
