[KWH]

To Dallas the person in Kansas.
Dallas, to assist you in better understanding the logic behind what the NFHS wants called and what they don't want called, the NFHS made Substitition and Participation a point of emphasis this year. In your 2004 rule book on pages 72 thru 74 they spelled out their philosophy along wih some case plays. It is well written and a good learning tool.
Example play 1 address your question.
Remember, however when reading it that if Johhny (A12) forgets to tell Billy (A11) that he is replacing him, "some judgment discretion in application is of the term immediatly" is required.
I hope this helps.