Well, if those numbers are correct, you are not too far off recommended levels. As the store suggested, you should raise you CYA up to 30-50. Also, you should try to keep your FC higher (3-5)..and this will be easier with correct CYA level.
Now, you should also understand that pool store results are not always the most accurate. It is highly recommended that you get a good test kit so you can test your own levels. I notice you are in Ontario, so I know that limits which kits you have access to.
Amen to that! I recently took 3 clean water bottles (like spring water type bottles) and grabbed samples. Put them in a black garbage bag and zipped off to 3 pool stores near each other. Three COMPLETELY different sets of numbers with three COMPLETELY different sets of recommendations - and ones that would conflict with each other as well!!