wip

app/Casts/RateCast.php

             return '0';
         }
 
-        $currency_code = $this->getDefaultCurrencyCode();
+        $currencyCode = $attributes['currency_code'] ?? $this->getDefaultCurrencyCode();
         $computation = AdjustmentComputation::parse($attributes['computation'] ?? $attributes['discount_computation'] ?? null);
 
         if ($computation?->isFixed()) {
-            return money($value, $currency_code)->formatSimple();
+            return money($value, $currencyCode)->formatSimple();
         }
 
         return RateCalculator::formatScaledRate($value);
 
         $computation = AdjustmentComputation::parse($attributes['computation'] ?? $attributes['discount_computation'] ?? null);
 
-        $currency_code = $this->getDefaultCurrencyCode();
+        $currencyCode = $attributes['currency_code'] ?? $this->getDefaultCurrencyCode();
 
         if ($computation?->isFixed()) {
-            return money($value, $currency_code, true)->getAmount();
+            return money($value, $currencyCode, true)->getAmount();
         }
 
         return RateCalculator::parseLocalizedRate($value);

app/View/Models/DocumentTotalViewModel.php

             return RateCalculator::calculatePercentage($subtotalInCents, $scaledDiscountRate);
         }
 
-        if (! CurrencyConverter::isValidAmount($discountRate)) {
+        if (! CurrencyConverter::isValidAmount($discountRate, $currencyCode)) {
             $discountRate = '0';
         }