That's correct! But I think Arandor is more concerned about the fact that even with good scouting and a successful clear (on the first try), it might not be possible to reach the minimum score for this map. And replaying once or ten times... it depends on who has the patience and time...
For example, let's take a situation where one player played once, and the other played ten times, but only achieved the same result as the first player on the 7th attempt, and all subsequent attempts were even better...
As a result, the rating will not quite accurately reflect the player's skill. But no better rules have been invented yet!