"According to the script you should be able to gain700 xp by playing chess (each game takes two hours) and getting a critical success on an IN check."
so: gain xp IF playing AND crit success.
where exactly in that equation do you see winning? critical success means critical success. no normal success mentioned. a normal success would imply winning, as that is kinda the meaning of the word success. with the current wording, it could be conceivable that you could have a normal success as well, but that that scenario does not award any bonus XP.
you call it comprehensive reading, i call it interpretation (the most likely meaning which Per probably meant, as said), however it's not there in writing.