Richard, yes it's me again.
I built a database with the city, county, zip, zip ext, state & country and I can lookup a zip code and it will tell me all I need to know about that area of the country.
Now I want to implement the sales tax I have to collect for the state of Texas.
We have 4 areas of tax to collect. I have put these areas into this table based on the zip code.

Now, when I do my sales orders & invoices, I have the tax totaled based on that customers location (ie. zip code).
The lovely state of Texas says we are not to collect more than 8.25% & some of these totals exceed this amount.

My question is, how can I limit the total to the 8.25% AND, in chronological order, have the last unit/area of tax collected be adjusted to maintain this limit?
We have, of course,

1) city
2) county
3) special purpose
4) transit tax

This is the order of importance we have to collect. (The transit tax will be the 1 to suffer the cut).

I also need to make a quarterly report to show these figures in their respective areas for paying the sales tax to the state.

Can, of course you can, WILL you shed some light on this for me?

P.S. I will be willing to share this table & form with anybody who wants it.
The tax portion will be exclusive to Texas though.