Yeah you definitely need to eat ghosts to score, I should specify that in my 489k run I only ever ate ghosts in the late game that were directly in my dot line. The graph says ghosts were the highest point source, but that’s only from intentional ghost chaining in the first minute.
From 2:45 to 3:45 I focused on fruits and those blue peaks are from ghost chains I managed to set up along the dot line. I don’t know how to actually set these up other than to improvise and time my power pellets for when a ghost spawns in the box. I consciously alter my dot route if I eat a ghost so that I save the next pellet for extending my invulnerability and hitting all four ghosts with it.
It goes without saying that no-miss is mandatory. Dying and respawning takes five seconds, a big flow breaker.