You can apply the same concept with groceries or engine oil. All it is, is being a smart shopper...
Would you buy a gallon of milk for $4.00, or 2 half gallons of milk for $2.50 each? They are both milk, just different container sizes.
Would you buy a 5 quart jug of engine oil for $25.00, or 5 quarts for $7.00 each? They are both engine oil, just different sizes.
the list goes on...
If you want to be technical, all items are the same brand.
imo of course.