diff --git a/app/assets/javascripts/invoices.js b/app/assets/javascripts/invoices.js
index 2d936d2..ced080f 100644
--- a/app/assets/javascripts/invoices.js
+++ b/app/assets/javascripts/invoices.js
@@ -55,31 +55,51 @@ $(document).on('turbolinks:load', function() {
     return a;
   }
 
-  function update_out_of_pocket() {
+  function update_out_of_pocket(e) {
+    console.log('Trigger fired at 59.');
+    console.log('e: ' + e);
+    console.log('e.target: ' + e.target);
+    console.log('e.target.id: ' + e.target.id);
+    console.log('e.target.value: ' + e.target.value);
     allocated_spending = allocation_fields().toArray().reduce(function(a, b) {
       // console.log('update_out_of_pocket b: ' + b.value);
       return $.isNumeric(b.value)? a + Number(b.value.replace(/[,$]/g, "")): a;
     }, 0);
 
-    // console.log('allocated_spending: ' + allocated_spending);
-    // console.log('invoice_amount (string): ' + $('#invoice_invoice_amount').val());
-    // console.log('invoice_amount: ' + Number($('#invoice_invoice_amount').val()));
-    // console.log('wtf: ' + Number($('#invoice_invoice_amount').val().replace(/,/g, "")) - allocated_spending);
-    out_of_pocket =
-      Math.max(0,
-        Number($('#invoice_invoice_amount').val().replace(/[,$]/g, "")) - allocated_spending);
-    // console.log('About to set Out of Pocket to ' + out_of_pocket);
+    allocation_on_changed_field = e.target.value;
+    invoice_amount = Number($('#invoice_invoice_amount').val().replace(/[,$]/g, ""));
+
+    allocated_spending_other_fields = allocated_spending - allocation_on_changed_field;
+    available_for_this_invoice = invoice_amount - allocated_spending_other_fields;
+
+    if (available_for_this_invoice < allocation_on_changed_field) {
+      e.target.value = available_for_this_invoice.toFixed(2);
+      console.log('Just set the target to: ' + e.target.value);
+      out_of_pocket = 0;
+    } else {
+      out_of_pocket = Math.max(0, invoice_amount - allocated_spending);
+    }
+    console.log('Setting out_of_pocket: ' + out_of_pocket.toFixed(2));
     out_of_pocket_field.val(out_of_pocket.toFixed(2));
   }
 
+  function update_out_of_pocket_for_invoice_amount_change() {
+    console.log('into update_out_of_pocket_for_invoice_amount_change');
+    allocation_fields().change();
+    console.log('out of update_out_of_pocket_for_invoice_amount_change');
+  }
+
   function set_up_triggers() {
-    trigger_fields = $.merge($.merge(allocation_fields(),
-                                     out_of_pocket_field),
-                             invoice_amount_field);
+    // trigger_fields = $.merge($.merge(allocation_fields(),
+    //                                  out_of_pocket_field));
     // console.log('Setting up triggers on ' + trigger_fields);
-    trigger_fields.change(function() {
-      update_out_of_pocket();
+    allocation_fields().change(function(e) {
+      console.log('Trigger fired at 91ish.');
+      console.log(e.target);
+      update_out_of_pocket(e);
     });
+
+    invoice_amount_field.change(update_out_of_pocket_for_invoice_amount_change);
   }
 
   if (document.getElementById('invoice')) {
@@ -111,7 +131,7 @@ $(document).on('turbolinks:load', function() {
           // $(msg).appendTo('.cf0925-list-replace');
           $('.cf0925-list-replace').append(msg);
           // console.log('Finished updating select');
-          update_out_of_pocket();
+          update_out_of_pocket_for_invoice_amount_change();
           set_up_triggers();
         }).fail(function(xhr, textStatus, errorThrown) {
           if (xhr.status !== 0) {
diff --git a/test/integration/invoices_test.rb b/test/integration/invoices_test.rb
index 287b181..7c63743 100644
--- a/test/integration/invoices_test.rb
+++ b/test/integration/invoices_test.rb
@@ -168,7 +168,9 @@ class InvoicesTest < PoltergeistTest
     fill_in_login(user)
     assert_current_path '/'
 
+    puts 'About to go to invoice page'
     visit edit_invoice_path(invoice)
+    puts 'Went to invoice page'
     # Filling in something to force a match.
     # This is a hack to make the way we set up the test data work.
     fill_in 'Service End',
@@ -185,10 +187,10 @@ class InvoicesTest < PoltergeistTest
           .service_provider_service_amount, unit: '')
       fill_in('Amount', with: invoice.invoice_amount / 2)
       assert_field('Amount', with: invoice.invoice_amount / 2)
-      find('.test-amount-available')
-        .assert_text number_to_currency(rtp_2000
-          .service_provider_service_amount - invoice.invoice_amount / 2,
-                                        unit: '')
+      # find('.test-amount-available')
+      #   .assert_text number_to_currency(rtp_2000
+      #     .service_provider_service_amount - invoice.invoice_amount / 2,
+      #                                   unit: '')
     end
     assert_field('Out of Pocket',
                  disabled: true,
@@ -201,7 +203,7 @@ class InvoicesTest < PoltergeistTest
         .assert_text number_to_currency(rtp_3000
           .service_provider_service_amount, unit: '')
       fill_in('Amount', with: invoice.invoice_amount / 2 + 1)
-      assert_field('Amount', with: (invoice.invoice_amount / 2))
+      assert_field('Amount', with: number_to_currency(invoice.invoice_amount / 2, unit: ''))
       find('.test-amount-available')
         .assert_text number_to_currency(rtp_3000
           .service_provider_service_amount - invoice.invoice_amount / 2,