It has always surprised me how lax retailers seem to be about pricing merchandise clearly, accurately and consistently. What could possibly matter more? How hard is it to have someone on staff regularly walk a store to find places where prices have been knocked off or never put up?

But there are even more subtle ways that pricing can be maddening, especially for the budget-watcher. Several readers have told me about their frustrations with "unit" pricing, because different brands of the same item can be priced in different measures. In addition to the sales price, for example, the price tag for one brand of orange juice might show the "price per ounce," while the tag for another brand of orange juice right next to it might list the "price per quart."

"That seems a deliberate attempt to foil the shopper's attempt to comparison-shop," wrote one reader.

But is it? In fact, retail experts say such discrepancies -- as when the scanner price doesn't match the shelf price -- are most often the result of simple sloppiness or lack of management attention, not a conspiracy to hide the true price difference between two competing brands.

Unit pricing is "one of those dumb things that's still done by manual data entry," said Mona Doyle, editor of the Shopper Report, a market research newsletter for the supermarket industry. One employee might enter the unit price for an item based on one measure, while the following week another worker might choose a different one.

But even if it's not a deliberate attempt to deceive, it certainly doesn't show a deliberate attempt to be clear. And that is the real problem.

Larger retailers are required to list unit prices, but the unit of measure they use is generally left up to them; there are only a handful of states that specifically dictate which measures must be used. New Jersey, for example, mandates that the unit price always be by the pound on cheese, by the quart on mouthwash and per 100 count on plastic bags.

Because retailers are usually the ones making the decisions on this issue, different chains may well choose different measurements for whole categories of goods. At Safeway in the Washington area, yogurt is priced per ounce, while Giant Food prices its yogurt per pound. On laundry detergent, Safeway gives the unit price per pound, while Giant gives the detergent price per load.

But even if a chain largely uses one particular measure, inconsistencies are easy to find. At Giant last week, for example, Nesquik flavored milk was $1.65 for a 16-ounce bottle, or $3.30 a quart. But right next to it, the competing container of Hershey's Creamy Chocolate Milk in a 14-ounce bottle was $1.59 and 11.3 cents an ounce. Nearby, three kinds of whipping cream had three different unit-price measures: per pint, per ounce and per quart.

"It's definitely human error," said Jannet Tenney, manager of nutrition programs for Giant, who added that "ketchup to ketchup should be comparable" when it comes to listing unit prices.

But with 30,000 different items in the store and hundreds of price changes per week, she said, some mistakes slip through because the information technology department puts the data in wrong. Store managers should be looking for such mistakes, she said, but won't always catch them. She asked that shoppers bring examples to the attention of store employees.

Tenney's explanation is typical: Such errors are bound to happen in a complex store. And, of course, that's true. But it also illustrates one of the consistent problems in chain retailing today, which is that executives, managers and even front-line employees have a hard time seeing the operation from any point of view but their own.

So, from their insider's vantage point, all they can see is that it's a daunting task to manage so many stores, or so many employees, or so many individual items for sale, and therefore mistakes are not only understandable, they're expected. So when a customer gets annoyed because a product rings up higher at the scanner than was shown on the shelf, retailers are mystified that that shopper assumes discrepancies are intentional. To them, it's just an honest mistake. Happens all the time.

But they're missing the point. Shoppers care about details. Maybe listing the unit price in a different measure isn't going to affect someone's buying decision, but it's still annoying. Slip-ups like that show an indifference to customers that builds up in shoppers' minds until they see a fundamental lack of caring in every little problem a store has. How hard would it be for a chain to just implement a company-wide standard for the data-entry folks who are making these decisions on the fly? Sloppiness does send a message.

"Retailers that are winning in the marketplace today are those that can do a couple of things," said Janet Hoffman, a partner in the retail practice at Accenture Consulting. "One, they have great insight into the consumer. Two, they are best equipped at what we call operational excellence -- and it is all around that level of detail and discipline orientation."

And in more traditional, non-discount retailing formats, pricing tends to be one of the first areas where sloppiness shows up. To these retailers, perfectly legible, consistent and obvious pricing isn't as high a priority as other things because, frankly, it's not their best asset.

"Discounters have a lot of incentive to make sure their pricing is really clear," said Lisa E. Bolton, assistant professor of marketing at the University of Pennsylvania's Wharton School. "If you're not a discount store, you don't want to go too far on making your pricing clear because you know you're not the lowest. It's just not a top concern for them to be clear."

So maybe the shoppers who ascribe sinister motives to retailers for their unit-pricing discrepancies -- and other pricing errors -- are right on some level. True, the mistake itself probably isn't deliberate, but somewhere in some executive suite someone has made a conscious decision not to fix the system.

If you have a question, comment or concern about what you see when you shop, send an e-mail to sellingus@washpost.com.