js-tygh-checkout-js.diff

diff --git a/js/tygh/checkout.js b/js/tygh/checkout.js
index 807aef7..8c36238 100644
--- a/js/tygh/checkout.js
+++ b/js/tygh/checkout.js
@@ -18,8 +18,26 @@
         }
 
         function displayRecalculate(form) {
-            form.find(place_order_buttons_selector).hide();
-            form.find(recalculate_buttons_selector).show();
+            var changed_groups = {
+                user_data: false
+            };
+
+            form.find(inputs_selector).each(function(){
+                var elm = $(this);
+                if (elm.attr('type') != 'hidden' && form_values[elm.attr('name') + '_' + elm.attr('id')] != getVal(elm)) {
+                    var elm_name = elm.attr('name');
+                    if (elm_name) {
+                        var elm_group = elm_name.split('[')[0];
+                        changed_groups[elm_group] = true;
+                    }
+                }
+            });
+
+            // require recalculate only when user data changed
+            if (changed_groups['user_data']) {
+                form.find(place_order_buttons_selector).hide();
+                form.find(recalculate_buttons_selector).show();
+            }
         }
 
         function saveFormValues(form) {