Doubtful,
Just looking at your figures, it would make sense to assume that she diluted your water by 50% and then multiplied your CYA result by 100%. If the previous test results were correct??? it would seem more likely that your CYA might be around 165 or half what she told you. If it's possible, I would have another store run the test or have the original store run it again and explain exactly how they are arriving at the 330 number.