State/Provincial Sales Tax Best Practice

[jasonwood]

I will soon have to collect sales tax in more than just my home province, and I'm wondering if there are any best practices in this matter.

I currently have a field for the rate (auto-enter the current Ontario tax rate), and a calculation field for the tax.

Do I go simple - just change the rate depending on the ship-to province, and carefully make sure that sales-tax-reports never combine them?

Or do I go a bit more complicated and add a new field, or (gasp!) a related table for sales tax. (might be an especially good idea if I plan to collect sales tax for a larger number of provinces in the future?)

I've noticed looking at other invoices that it seems to be a common practice to make sales tax a regular line item and sort to the bottom (I base that on its position on the invoice). Wondering if that's the common way to do it?

[mr_vodka]

If there are going to be different sales tax rates for different areas, I would store them in a seperate table. Even if there was ONLY one, I would still store the rate in a preferences table.

[jasonwood]

I'm pretty happy putting the rate right into the invoice creation script or as an auto-enter calc - it doesn't have to be modifiable by anyone but me. I was wondering about the actual sales tax amount field itself.

I could certainly use one field to calculate the sales tax regardless of the province, as long as I remember that reports need to be designed so as not to present a sum of this field that includes invoices from different provinces - I might inadvertently pay all of my sales tax collected to a single tax authority, for example.

I was just wondering if there were any good arguments in favor of using another method instead, such as putting every sales tax amount in a related record, which appears to be a common practice.