I will hazard a guess that what you are consuming is not what you are spending.
for example, you get a big order from Place X, so you just spent that. But, you aren't going to eat that entire order this week, some of it you will store. In addition to the items from Place X you might enjoy this week, you may add a few steaks or sides from previous orders in previous weeks. Maybe have some ice cream that came in yet a third or 4th order, maybe this week, maybe not.
I think if you priced out the cost of what you are consuming, you would find savings. Frankly, a big pain in the butt (how much did this 1/4 cup of sugar or 8 strawberries actually cost??), however, I would guess that your savings are in the consuming and not in the buying. It's easy in restaurants - this item is this cost and you don't have to care how much individual ingredients cost, nor if the entire ingredient were used in that meal or if it stretched across the entire night of servings they prepared (I dunno, could be a bunch of parsley garnish or massive tub of flour).
Not sure I expressed that well.... so, short it to, unless you are perfectly buying and consuming only those buys in that time period, you won't see it. Counting how many times I use 1 tsp of salt just isn't something I would do, I know the container lasts many many months, and I'm not sure how many.