See The hubris of calendrical calculations. And Calendrical Calculations, Part 2.
"Here are the exact words from the client when I suggested using the "official calendar": I’m aware of other systems having tables for Holidays but I don’t know that we can piggy back off any of them (not aware they are publicly available). Besides, I’d rather we have better control over our own destiny than relying on someone else. As far as Month End is concerned, we have unique needs that only system x might operate in a similar fashion but that too is user entered"
This came up in a discussion of how to find the "first business day" of a month. Clearly, using the RDBMS calendar functions to find the first day of the month is completely wrong, since it doesn't account for legal holidays in any form. So, the approach suggested was to add tables and programming logic to -- essentially -- approximate the calendar information already available in the General Ledger.
The very idea of reuse was a non-starter. This response characterizes the impassible barrier to SOA: "I’d rather we have better control over our own destiny than relying on someone else".
Worse still is the idea that the "user-entered" business calendar (the one actually used by the business) isn't appropriate, and an algorithmic approximation -- in spite of the inevitable errors -- is somehow better. It's almost as if the official business calendar is not trustworthy because it is tweaked by accountants to get the number of business days and holidays to balance in each period.
The simple idea of reuse is lost in the politics of who controls who's fate. Does anyone else find this behavior fringing on the criminal?