Hey PopPop, I agree, sometimes it is hard to distinguish between lines that never meet and bullet travel that crosses your sight setting.For most shooters, understanding Line of sight and line of bore are all that matter, that and dismissing from your mind that a bullet can ever rise above line of bore. It does indeed begin to drop and continues to drop until gravity drives it to earth.
With a properly mounted scope, centered over the bore, line of bore and line of sight are never perfectly parallel and the bullet will cross that line of sight twice, once near the muzzle and once further down range.