diff --git a/frontend/rctool/templates/rctool/rctool/develop/rctool_develop_js.html b/frontend/rctool/templates/rctool/rctool/develop/rctool_develop_js.html
index e37a26f..f095bea 100644
--- a/frontend/rctool/templates/rctool/rctool/develop/rctool_develop_js.html
+++ b/frontend/rctool/templates/rctool/rctool/develop/rctool_develop_js.html
@@ -1262,6 +1262,8 @@
                     callbacks: {
                         label: function(context) {
                             var label = context.dataset.label || '';
+                            let h_field = context.parsed.y
+                            let q_field = context.parsed.x
 
                             // get toggle state of toggle_detailed_tooltip
                             var toggle_detailed_tooltip = document.getElementById("toggle_detailed_tooltip").checked
@@ -1270,7 +1272,7 @@
                                 label = [];
                                 if (toggle_detailed_tooltip == true) {
                                     for (var idx in fielddatacsv.stage) {
-                                        if (fielddatacsv.stage[idx] == context.parsed.y && fielddatacsv.discharge[idx] == context.parsed.x) {
+                                        if (fielddatacsv.stage[idx] == h_field && fielddatacsv.discharge[idx] == q_field) {
 
                                             // find discharge from rating curve for this stage
                                             let q_model = null
@@ -1281,18 +1283,18 @@
                                                 for (var j in residualData[seg].data){
                                                     if (residualData[seg].data[j][0] == fielddatacsv.stage[idx]){
                                                         q_model = residualData[seg].data[j][1]
-                                                        h_model = calc_h_model(context.parsed.x, rcParam[seg - 1].const, rcParam[seg - 1].exp, rcParam[seg - 1].offset)
-                                                        r_percent = calc_residual_percent(context.parsed.y, context.parsed.x, rcParam[seg - 1].const, rcParam[seg - 1].exp, rcParam[seg - 1].offset)
-                                                        r_volumetric = r_percent/100 * context.parsed.x
+                                                        h_model = calc_h_model(q_field, rcParam[seg - 1].const, rcParam[seg - 1].exp, rcParam[seg - 1].offset)
+                                                        r_percent = calc_residual_percent(h_field, q_field, rcParam[seg - 1].const, rcParam[seg - 1].exp, rcParam[seg - 1].offset)
+                                                        r_volumetric = r_percent/100 * q_field
                                                     }
                                                 }
                                             }
-                                            label.push(['H:       ' + context.parsed.y.toFixed(2) + ' m']);
-                                            label.push(['Q:       ' + context.parsed.x.toFixed(2) + ' m³/s']);
+                                            label.push(['H:       ' + h_field.toFixed(2) + ' m']);
+                                            label.push(['Q:       ' + q_field.toFixed(2) + ' m³/s']);
                                             label.push(['date:    ' + fielddatacsv.datetime[idx]]);
                                             if (h_model !== null) {
-                                                label.push(['H shift: ' + (h_model - context.parsed.y).toFixed(2) + ' m'])
-                                                label.push(['H shift: ' + (h_model - context.parsed.y).toFixed(2) + ' m'])
+                                                label.push(['H shift: ' + (h_model - h_field).toFixed(2) + ' m'])
+                                                label.push(['H shift: ' + (h_model - h_field).toFixed(2) + ' m'])
                                             }
                                             //if (q_model !== null){
                                             //    label.push(['Q model: ' + q_model.toFixed(2) + ' m³/s']);
@@ -1310,8 +1312,8 @@
                                         }
                                     }
                                 } else {
-                                    if (context.parsed.y !== null) {
-                                        label.push(['stage: ' + context.parsed.y.toFixed(2) + ' m, discharge: ' + context.parsed.x.toFixed(2) + ' m³/s']);
+                                    if (h_field !== null) {
+                                        label.push(['stage: ' + h_field.toFixed(2) + ' m, discharge: ' + q_field.toFixed(2) + ' m³/s']);
                                     }
                                 }
                             }
@@ -1506,11 +1508,11 @@
 
                                 for (var idx in fielddatacsv.stage) {
                                     if (fielddatacsv.stage[idx] == h_field && fielddatacsv.discharge[idx] == q_field_rounded) {
-                                        label.push(['H:       ' + context.parsed.y.toFixed(2) + ' m']);
-                                        label.push(['Q:       ' + context.parsed.x.toFixed(2) + ' m³/s']);
+                                        label.push(['H:       ' + h_field.toFixed(2) + ' m']);
+                                        label.push(['Q:       ' + q_field.toFixed(2) + ' m³/s']);
                                         label.push(['date:    ' + fielddatacsv.datetime[idx]]);
                                         if (h_model !== null) {
-                                            label.push(['H shift: ' + (h_model - context.parsed.y).toFixed(2) + ' m'])
+                                            label.push(['H shift: ' + (h_model - h_field).toFixed(2) + ' m'])
                                         }
                                         //if (q_model !== null){
                                         //    label.push(['Q model: ' + q_model.toFixed(2) + ' m³/s']);