first of all 1 in 3 times means you will make it 1 time every 3 and not make it 2 times in every 3. So the odds against making it are 2:1.

Secondly, you were reading about the odds of making your flush on the next card which IMO is a much more sensible way of calculating whether or not you should be calling bets in NL because you have no idea what the bet sizes are going to be in future betting rounds. Chance of making flush with the next 1 card is about 20% or 1 in 5.

1 time you will make it
4 times you will not

odds of 4:1 against making it (i.e. 4:1 actually means 1 in 5 chance)