See my edit above. You're right, they're pretty close, but actually it's Blaziken hitting both with neutral STAB, which gives it an advantage.AH you're right, 154/373 maximum. Still, why wasn't Gen III perfectly balanced? Sceptile had Leaf Blade for Swampert, Swampert had Earthquake/Muddy Water for Blaziken, and Blaziken had Blaze Kick for Sceptile. Sceptile couldn't OHKO Blaziken with Earthquake, either. To be honest, I don't really mind if this generation is balanced. I loved the challenge of Generation III and using Sceptile or Swampert, because I had to catch something like Taillow or Wingull lest I lose to my rival under the Mauville Bridge.
@ Fizz
Obviously, starters are balanced when the effectiveness of the one your rival picks over the one you pick is the same for any pokemon you can pick.
A good example is gen2: Your rival hits your starter super effective with his STAB, while you hit him not very effective with your STAB moves, but you can have a non-STAB move to hit him super-effective. That works, regardless of which pokemon you actually pick.
A bad example is gen3: If you pick Infernape, your rival picks Empoleon. Nonetheless, you can easily beat Empoleon with fighting STAB. That's truely bad balance. lol