diff --git a/app/services/voucher_adjustments_service.rb b/app/services/voucher_adjustments_service.rb
index 13f818a8dc5..cfc1bab994b 100644
--- a/app/services/voucher_adjustments_service.rb
+++ b/app/services/voucher_adjustments_service.rb
@@ -10,17 +10,14 @@ def self.calculate(order)
     # We only support one voucher per order right now, we could just loop on voucher_adjustments
     adjustment = order.voucher_adjustments.first
 
-    # Recalculate value
     voucher = adjustment.originator
-    # TODO: see if we can remove this and do it in  handle_tax_excluded_from_price
-    amount = voucher.compute_amount(order)
 
     # It is quite possible to have an order with both tax included in and tax excluded from price.
     # We should be able to caculate the relevant amount apply the current calculation.
     #
     # For now we just assume it is either all tax included in price or all tax excluded from price.
     if order.additional_tax_total.positive?
-      handle_tax_excluded_from_price(order, amount)
+      handle_tax_excluded_from_price(order, voucher)
     else
       handle_tax_included_in_price(order, voucher)
     end
@@ -29,8 +26,13 @@ def self.calculate(order)
     adjustment.close
   end
 
-  def self.handle_tax_excluded_from_price(order, amount)
-    voucher_rate = amount / order.total
+  def self.handle_tax_excluded_from_price(order, voucher)
+    if voucher.voucher_type == Voucher::FLAT_RATE
+      amount = voucher.compute_amount(order)
+      voucher_rate = amount / order.total
+    else
+      voucher_rate = -voucher.amount / 100
+    end
 
     # Adding the voucher tax part
     tax_amount = voucher_rate * order.additional_tax_total
diff --git a/spec/services/voucher_adjustments_service_spec.rb b/spec/services/voucher_adjustments_service_spec.rb
index 555ab746bd1..77e3cc85960 100644
--- a/spec/services/voucher_adjustments_service_spec.rb
+++ b/spec/services/voucher_adjustments_service_spec.rb
@@ -209,22 +209,22 @@
           VoucherAdjustmentsService.calculate(order)
         end
 
-        pending 'includes amount withou tax' do
+        it 'includes amount without tax' do
           adjustment = order.voucher_adjustments.first
-          # voucher_rate = amount / order.total
-          # -10 / 161 = -0.062111801
-          # amount = voucher_rate * (order.total - order.additional_tax_total)
-          # -0.062111801 * (161 -11) = -9.32
-          expect(adjustment.amount.to_f).to eq(-9.32)
+          # voucher_rate = voucher.amount / 100
+          # 10 / 100 = 0.1
+          # amount = -voucher_rate * (order.total - order.additional_tax_total)
+          # -0.1 * (166 -11) = -15.5
+          expect(adjustment.amount.to_f).to eq(-15.5)
         end
 
-        pending 'creates a tax adjustment' do
-          # voucher_rate = amount / order.total
-          # -10 / 161 = -0.062111801
-          # amount = voucher_rate * order.additional_tax_total
-          # -0.0585 * 11 = -0.68
+        it 'creates a tax adjustment' do
+          # voucher_rate = voucher.amount / 100
+          # 10 / 100 = 0.1
+          # amount = -voucher_rate * order.additional_tax_total
+          # -0.1 * 11 = -1.1
           tax_adjustment = order.voucher_adjustments.second
-          expect(tax_adjustment.amount.to_f).to eq(-0.68)
+          expect(tax_adjustment.amount.to_f).to eq(-1.1)
           expect(tax_adjustment.label).to match("Tax")
         end