Some calculations don't need to be done that often. Recalculating for a massive data set can often be.. fudged for a period of time, in scientific computing - accuracy decreases over time, and then a full recalculation is eventually necessary. If you need major computing power, but only need it twice a month, this type of plan is economical, whether you're a large company or a small one.

The size of the enterprise is not always in proportion with the size of the datasets.