diff --git a/app/models/concerns/spree_taxjar/taxable.rb b/app/models/concerns/spree_taxjar/taxable.rb
index 4f3f2a3..014804c 100644
--- a/app/models/concerns/spree_taxjar/taxable.rb
+++ b/app/models/concerns/spree_taxjar/taxable.rb
@@ -5,7 +5,10 @@ module Taxable
     private
 
     def taxjar_applicable?(order)
-      ::Spree::TaxRate.match(order.tax_zone).any? { |rate| rate.calculator_type == "Spree::Calculator::TaxjarCalculator" }
+      ::Spree::TaxRate.joins(:calculator)
+                      .match(order.tax_zone)
+                      .where(spree_calculators: { type: ::Spree::Calculator::TaxjarCalculator.to_s }  )
+                      .any?
     end
   end
 end
diff --git a/app/models/spree/calculator/taxjar_calculator.rb b/app/models/spree/calculator/taxjar_calculator.rb
index 06a390d..d48fa42 100644
--- a/app/models/spree/calculator/taxjar_calculator.rb
+++ b/app/models/spree/calculator/taxjar_calculator.rb
@@ -96,7 +96,7 @@ def cache_key(order, item, address)
         if item.is_a?(Spree::LineItem)
           [Spree::LineItem.to_s, order.id, item.id, address.state_id, address.zipcode, item.taxable_amount, :amount_to_collect]
         else
-          [Spree::Shipment.to_s, order.id, item.id, address.state_id, address.zipcode, item.cost, item.adjustments.select { |adjustment| adjustment.source_type != Spree::TaxRate.to_s }.map(&:amount).sum.to_f, :amount_to_collect]
+          [Spree::Shipment.to_s, order.id, item.id, address.state_id, address.zipcode, item.cost, item.adjustments.where.not(source_type: Spree::TaxRate.to_s).sum(:amount), :amount_to_collect]
         end
       end
   end
diff --git a/app/models/spree/taxjar.rb b/app/models/spree/taxjar.rb
index 229504e..e054cf9 100644
--- a/app/models/spree/taxjar.rb
+++ b/app/models/spree/taxjar.rb
@@ -118,7 +118,7 @@ def tax_params
       end
 
       def taxable_line_items_params
-        @order.line_items.map do |item|
+        @order.line_items.includes(:variant, :product, :tax_category).map do |item|
           {
             id: item.id,
             quantity: item.quantity,
@@ -189,7 +189,7 @@ def shipment_tax_params
       end
 
       def line_item_params
-        @order.line_items.map do |item|
+        @order.line_items.includes(:variant, :product, :tax_category).map do |item|
           unit_price = item.taxable_amount / item.quantity
           {
             quantity: item.quantity,
@@ -210,7 +210,7 @@ def discount_weightage(item, unit_price)
       end
 
       def adjustments_total(adjustments)
-        adjustments.select { |adjustment| adjustment.source_type != Spree::TaxRate.to_s }.map(&:amount).sum.to_f
+        adjustments.where.not(source_type: Spree::TaxRate.to_s).sum(:amount)
       end
 
       def client_params
diff --git a/spec/controllers/spree/admin/taxjar_settings_controller_spec.rb b/spec/controllers/spree/admin/taxjar_settings_controller_spec.rb
index 8d08275..8b0825a 100644
--- a/spec/controllers/spree/admin/taxjar_settings_controller_spec.rb
+++ b/spec/controllers/spree/admin/taxjar_settings_controller_spec.rb
@@ -21,7 +21,7 @@ def send_request
     end
 
     it "assigns @preferences_api" do
-      expect(assigns[:preferences_api]).to eq([:taxjar_api_key, :taxjar_enabled, :taxjar_debug_enabled])
+      expect(assigns[:preferences_api]).to eq([:taxjar_api_key, :taxjar_enabled, :taxjar_debug_enabled, :taxjar_sandbox_environment_enabled])
     end
 
     it "renders edit template" do