re: Can somebody explain Goran Ivaniševic's 2nd serve strategy to me?

In word-problem-world, absolutely. But these don’t seem like truly independent events.

Depending on the temperament of the player, I could see a missed first serve either rattling them or helping them calibrate for the second attempt. For a player committed to taking two bites at the apple and therefore relatively unfazed by a first-serve fault, they might be able to improve their accuracy on the second attempt. Would be interested to see stats for Ivanisevic