>>282123437
It doesn't skip over chapters, but it does add in chapters/scenes to the original manga he drew decades later, especially obvious in Getter Robo G's climax.
I can't confirm this one but it may have also compressed the original run's chapters, because I really can't imagine that 100+ chapters were a thing that actually happened in magazines.
Also, unlike the anime, the original manga never changed titles, it was all Getter Robo, no Getter Robo G