Normally the values should be directly updated to the CSV file.
Probably most of the nightmare is because you have a different account for each taxes in the system. So when the taxes are updated the chart should be updated.
I must admint that we had that on the first versions of the Spanish Chart of accounts and that caused a lot of maintenance noise. We had this design because we inherited that from other accounting systems. Even now, some accountants asks for such setup because they are used to other softwares where tax reporting is linked to accounting.
As Tryton is splits tax reporting from accounts, you can have all the tax related to a single account (one for payable other for receivable) so you do not need to change the account chart when the taxes are updated. You just need to update the taxes.