Good question. The count (20 or 10)
depends upon possession in high school (Federation). All you said appears to be true if I understood you correctly. Yes, there are times in fed where there is no count. IE, A player, long pole, in his defensive end of field passes the ball forward across midfield and no possession is achieved- ball is being kicked around- so NO count. But if that same long pole carried ball across midline and was checked immediately, losing control/possession, the 10 sec count starts when he crossed midline.