Similar to the limitations listed at: https://help.zoho.com/portal/en/community/topic/zoho-finance-limitations-2-0-12-cant-sync-books-system-fields-item-category-or-preferred-vendor-to-crm-products-double-entry-required
Summary:
Our reps add customer accounts which are sometimes tax exempt and thus have a exemption number. When the rep adds this data to the CRM account we would like it to sync with the Books Customer Account but we can't because the respective system field is not available as a sync option so double entry is required.
Manual Solution
Everytime you add an account with this information you have to contact the accounts team and have them manually update on the Books side.
Once it's set at the account level, Sales Tax will not be applied by default. Note: We use the Avalara tax integration.
Another option is to just set the Tax code manually each time you enter an order.
Allow these system default tax fields to be synced so the management or the account can be done on either Books side or the CRM user side.