Double DIFAL taxable basis calculation

Summary:

In Brazil, we have a tax named as DIFAL (it's the ICMS rate difference between ship to and ship from states).

The standard DIFAL we developed a logic to get it calculated perfectly.

Now, we need to create the double taxable basis for São Paulo. Let me share some values as example:

/*** EXAMPLE ***/

from MT to MG

Transaction value: R$1000

ICMS Interstate: 12%

ICMS Intrastate: 18%

=((Transaction value - (Transaction value * ICMS Interstate)) / (1 - ICMS Intrastate) * ICMS Intrastate) - (Transaction value * ICMS Interstate)

=((1000 - (1000 * 12%)) / (1 - 18%) * 18%) - (1000 * 12%)

/****************/

Has someone faced this calculation already?

Content (please ensure you mask any confidential information):