Production run size dictates the cost of the production run.
There will almost be a minimum size run to make it cost effective - think factors of production.
Smaller runs will increase transportation cost.
Smaller runs will also increase accounts receivable, which will ultimately lead to the need of more cash which could potential lead to additional debt.
There's a lot of logistics involved though because they're using an independent bottler to do their bottling. They can't just bottle a varying amount every week. They have to plan ahead with their best estimate of what they're going to need, and fit it into the independent bottler's schedule. The setup and teardown time before and after each bottling run takes time. So bigger orders that are carefully planned out are better because they're more efficient. As they grow larger and spread out to more stores and other markets, they will be doing even larger orders.