WTF?

[tesla]

Oddly enough, this story did *NOT* come from the Onion:

99¢ Only Stores®, in Response to Dramatically Rising Costs and Inflation, is Forced to Announce Its First Ever Price Increase, Raising Its Top Price from 99¢ to 99.99¢, Which is an Increase of Almost a Whole Penny

The New Maximum Retail Price will Still Be Just under a Dollar

(Full story here)

I realize that this isn't intended to be met with rational thought, but the first thing that occurs to me is "so the first 50 things you buy will be rounded up to $1.00, then the next one will cost $0.99, and so on, right?  I wonder whether they're testing their registers to ensure that happens."  This is going on in California, where they're really strict about advertised-price laws.

Comments

[sethb.livejournal.com]

Nope: if they round, the first 50 items will cost $1.00, the next one will cost $.99, the next 49 will cost $1.00, lather, rinse, repeat.

However, since there is sales tax, the actual pattern will be more complex.

[tesla-aldrich.livejournal.com]

Oops; right you are. See what I get for attempting computation while asleep?!

[guppiecat]

Is it common for POS systems to "round as you go"?

Most of the financial systems I've worked with end to assume that all transactions go to the hundred thousandths place and then round at the end.

In other words, it'd be:

  0.99990
+ 0.99990
+ 0.99990
+ 0.99990
+ 0.99990
+ 0.99990
+ 0.99990
+ 0.99990
---------
  7.99920
+  .47995  (6% Sales Tax in IA)
---------
  8.47915

And then it rounds to $8.48 to be displayed to the customer.


I can see that POS systems might have memory/processing limits that would make it better to round as you go, I've just never personally encountered it.

Maybe I'm insufficiently algorithmic.


(Edited to make the numbers lined up. In this instance, being picky is justified.)

[tesla-aldrich.livejournal.com]

I don't think I'm talking about "round as you go." My (admittedly limited) experience has been with POS systems that calculate a subtotal on the basis of items whose prices are stated in whole cents, then calculate and round tax and add it to the subtotal. The systems I'm talking about would choke if they were faced with something that cost $0.9999; I'm not sure that would even be valid input. At best they would round each item to $1.00

Finance systems are a different animal, of course. Accountant are expected to think in hundredths of cents; it's conflated with their reputations for being such scintillating characters.