Pitt/OKState clock error

[TriggerMN]

30.1 seconds left in the Pittsburgh-Oklahoma State game. Pitt down 3, shooting the 2nd free throw of 2. Free throw is missed. Pitt rebounds, passes, and makes a 3-pointer to tie the game. The clock never started until the ball passed through the hoop. At this point it starts while Oklahoma State is attempting to inbound. It runs down to 24.2 before it stops on the official's whistle.

After reviewing the play on the monitor, the officials put 25.1 seconds on the clock.

Can someone give a rule reference as to why?

With no definite knowledge of how much time should have run off, shouldn't they set it back to 30.1 and chalk it up to a timer's error? Can NCAA officials use a stopwatch and a monitor to correctly determine how much time to take off the clock in this situation?