I urge customers to buy the grey sticks, not the yellow just because of the way they fit into the filter standpipe. But the contents, usage and life-expectancy are all the same.
Best bet: shop online and find your very best price (don't forget to add shipping costs if any) and take a copy of that to your dealer. I had people do this all the time, and I would gladly match that price IF they bought ten at a time. Most did, to my delight!
HTH