How tall will it grow? My wife want a tree not a bush. Was looking at Fraser's photinia which is supposedly the same

This Red Tip is more of a tree than a bush. It will grow up to 15-20 feet tall

I purchased this under the assumption that this is the same as the red tip Bush that can get up to five feet tall or more. Is this not the case?

Yes the the red tip photinia bush will grow to over 5 feet.