Update Checkout table on tab

Hello everyone
I have one question.

I am using your great plugin. However I am encountering an error with the billing city field.

I have a reduced tax for some cities. I am using the billing_city for this when a user orders from a specific city (out of 5 cities) then a different VAT is applied.
The default checkout form is updating the checkout totals table when writing the city and hit the “TAB” or by changing the cursor .

However when I use your plugin when I change the field (I move the cursor from the billing_city to another field) the checkout table is not refreshed so the new VAT is not applied.

Is there any workaround?
All the best
Archimidis