That is not correct. Full training isn't determined by minutes, it is determined by the number of seconds. 48 minutes = 2880 seconds. That is how many seconds are required for full training, if you get 47 minutes and 40 seconds then you are 20 seconds less than full training and so you only get 2860 seconds worth of training. However, you would still get about 95% of training.
A BB posted about this sometime this week.