I've noticed this with Jameson too - he is currently eating less of the bisquits, so for now he gets bisquits plus half pouch of Whiskas in the morning, bisquits out throughout the day, and in the evening he'll get a pouch of Hi Life Essentials - the other 1/2 of the Whiskas pouch he gets the next morning (mixed with warm water)
And I know what you mean about your cat going crazy in the kitchen - EVERY time I open Jamesons food cupboard he's there faster than a lightning bolt, sniffing around and climbing the tins and boxes and seems very concerned about what I'm selecting for him!!!