MAF Controller; providing OJT; described an operational deviation event discovered during a facility tape review.

Narrative

I was providing OJT on the Local Control position at MAF tower. WX was 1/4 FG and 2 OVC. The ILS Runway 10 was the advertised approach; Runway 16R was the advertised departure runway. (Wind 190 at 11) Automatic releases were in effect for Runway 16R. Aircraft called ready at Runway 10; and the developmental cleared him for takeoff. I reminded them that they did not have a release and instructed to coordinate. The release from the Radar Controller was received prior to aircraft rounding the corner and beginning takeoff roll. The CIC and myself considered this a non event and a regular part of OJT on this position. I was advised later that this was being processed as an OD. If I can't let the developmental make a minor mistake and correct it; how are they going to learn. Even though 2 came before 1; no deviation occurred because it was corrected prior to the aircraft starting takeoff roll. Recommendation; I would suggest that along with the other parts of QA; a reality check be incorporated into the process of investigation. I was not even asked what happened until I was taken to listen to the tapes. The tapes did clearly show that only 13 seconds elapsed between takeoff clearance and the release. Even if the letter of the law was not followed; the spirit surely was. Plus a new developmental learned that there is more to saying cleared for takeoff. This event was discovered during a review of the following arrivals missed approach. No errors were found in the missed approach event; but this was found in the review.