Sure Jim,

For example in Canada...
Ontario: 7% federal + 8% provincial = 15% (Wired in parallel)
Quebec: 7% federal + 8% provincial on (value+ federal)= 15.56% (Wired in series)

Not only does this suck, but in some jurisdictions in other countries things like baby clothes, heating oil, and books are taxed, and in others they are tax exempt, or taxed federally but not provincially. You want objects to hide these sorts of implementation details from the mainline code...

**--** Steve

>Sorry to jump back into an old thread, Steve, but could you give me a real world example of this series vs parallel tax business? Series I see as the purchaser paying Fed+State+local. But parallel? Do you mean this in a tax reporting context?
>
>>In our case, behind the scenes, we instantiate separate implementation objects for municipal, state, and federal taxes, and these get combined in series or in parallel depending on whether taxes are additive or whether they piggyback.
>>
>>**--** Steve
>>