Sugar and a math question: When does 25 ÷ 5 not equal 5?

Recently I purchased a 25 pound bag of Imperial Sugar at Costco for $8.99.  Yesterday I separated the bag, planning to store the sugar in 5 pound bags.  I carefully measured and weighed each amount on my digital scale.  In the end I was left with 4 pounds for the remaining bag.  When did 25 lbs divided
by 5 not equal 5?   I ended with (4) 5 pound bags and (1) 4 pound bag.  No big deal you say. 

On its own, I would agree.  It amounts to a mere $.3596 for the missing pound of sugar.  However, at 3 million pounds (an amount Imperial sells while we are having our first cup of morning coffee) amounts to a staggering $1,078,800!  

Imperial owns in excess of 80% of the world market share with assets in over 100 locations around the world.

For one, I would like to know if this practice is that of Imperial Sugar Company, or is it a practice of short-changing product at Costco in the manner Walmart forces their suppliers to do in order to keep the prices lower than the competition.

Either way, it is once again the unaware public, us, who end up losing while the upper 10% fill their pockets with our money.

This is one of those topics which just sets me off ranting yet again.  Imperial does offer a $.50 coupon on the next purchase, which more than replaces cost of the missing pound, and if that were my only issue I would gladly use the coupon and move forward.  For me, however, it is more than the pennies, it is the principle that gnaws at me.  These corporations who feel it is alright to trick the public out of millions of dollars each day and no one suspects.

Isn't it enough they don't pay their fair share, if any, taxes?;  have the government in their pockets and the run the world?