Have you checked the "index flat spring" (indicated in the parts diagram) or the gearing? Does the reel feel loose on the shaft (left-right or up-down relative to the attached diagram)? I know it's happening on all four hundreds reels, but it looks like the reel in the video is skidding through some numbers. Hundreds reels don't have the circuit card, do they need a spacer under the C clip to compensate for the missing card?
Score reel (resized).jpg