Advertising so Obvious a 10 Year Old Can See Through It

I'm watching TV with my 10 year old son and a Tide commercial came on which my son saw right through. Tide's ad is showcasing their 2x ultra tide and how their product has less water then the others original laundry detergent (that's in the small print.) The ad shows how much of the competitors bottle is detergent vrs water content compared to their bottle which has twice as much detergent vrs water content. The voice over then states: "When you pay for detergent you get more detergent" Sounds straight forward right?.....

My son turned to me and says "ya except their bottle is smaller so its the same amount of detergent." So if a 10 year old can see through the ad is it effective? Do I really want to spend more money for Tide then another brand because I'm getting the same amount of detergent then the regular brand? Not really.