@hitless45 has it right. The "not over the batter's head" used to be included in the description of a foul tip but all that did was make it so that a ball that was hit backward and higher than the batter's head could not be a foul tip. They removed that quite some time back.
But here is my dissertation is many, many more words.
Definition time. A foul tip is a pitched ball, struck by the batter that goes
sharply and directly to the catcher's hand or glove
and is caught. If it meets this definition, it is a foul tip and a strike (ball remains live in some games like FP, modified, SP with stealing). If it's strike three then the batter is out.
Any batted ball that doesn't conform to this definition is not a foul tip and you treat it like any other batted ball. If it's legally caught before it hits the ground, fence, etc. then it's caught for an out. If it's not legally caught, you apply the fair/foul rules (where was it first touched/came to rest) - likely just a foul ball.
While not in the definition, most umpires will view that as "any hit ball that has any kind of arc to it is not a foul tip" which is not unreasonable. Realistically, a true foul tip is uncommon in the game of slow pitch and very common in the fast pitch game. The ruleset covers both so the definition is there.
TL/DR -
@hitless45 has it right. Above the head doesn't matter.