The structure that makes a veterinary practice readable is a set of revenue centers — professional services, pharmacy, prescription diet, over-the-counter product, laboratory, imaging, dentistry, boarding, grooming — with a cost of goods or supply account matched to each.
The pairing is the whole point, and it is the part most often lost when a practice sets up its own chart. Revenue centers on their own produce a nicely detailed income statement and no margins, because every purchase still lands in one general account. A center matched to its cost tells you what that part of the practice actually returns: whether the pharmacy is carrying the clinic or the clinic is subsidising the pharmacy, whether diet sales are worth the shelf space and the working capital tied up in them, whether boarding covers its own staffing. Those are the questions practice owners ask, and a pooled file cannot answer any of them regardless of how carefully the income side was built.