diff --git a/api/experiments.ts b/api/experiments.ts
index 0adffc3..2557fe5 100644
--- a/api/experiments.ts
+++ b/api/experiments.ts
@@ -85,6 +85,7 @@ export default async function handler(req: VercelRequest, res: VercelResponse) {
     if (req.method === 'PUT') {
       const { id } = req.query;
       const updates = req.body;
+      console.log('Update payload for id', id, ':', updates);
 
       const { data, error } = await supabase
         .from('experiments')
diff --git a/components/ExperimentDetail.tsx b/components/ExperimentDetail.tsx
index 203ee56..1c2c924 100644
--- a/components/ExperimentDetail.tsx
+++ b/components/ExperimentDetail.tsx
@@ -55,9 +55,12 @@ const ExperimentDetail: React.FC<ExperimentDetailProps> = ({ experimentId, onClo
     setLoading(true);
     try {
       const perf = await calculateExperimentPerformance(experiment, salesData);
+      console.log('Calculation yielded performance delta payload:', perf);
       const updated = await updateExperiment(experiment.id, perf);
+      console.log('Update return from backend:', updated);
       setExperiment(updated);
     } catch (e: any) {
+      console.error('Full calculation error:', e);
       alert(`Error calculating results: ${e.message}`);
     } finally {
       setLoading(false);
diff --git a/services/experiments.ts b/services/experiments.ts
index 67f625f..ca6cdd1 100644
--- a/services/experiments.ts
+++ b/services/experiments.ts
@@ -59,18 +59,27 @@ export const updateExperiment = async (
   id: string,
   updates: Partial<Experiment>
 ): Promise<Experiment> => {
-  const response = await fetch(`${API_BASE}?id=${id}`, {
-    method: 'PUT',
-    headers: { 'Content-Type': 'application/json' },
-    body: JSON.stringify(updates),
-  });
+  try {
+    const response = await fetch(`${API_BASE}?id=${id}`, {
+      method: 'PUT',
+      headers: { 'Content-Type': 'application/json' },
+      body: JSON.stringify(updates),
+    });
 
-  if (!response.ok) {
-    const error = await response.json();
-    throw new Error(error.error || 'Failed to update experiment');
+    if (!response.ok) {
+      let errText = await response.text();
+      try {
+        const errJson = JSON.parse(errText);
+        errText = errJson.error || errText;
+      } catch (e) { }
+      throw new Error(errText);
+    }
+
+    return response.json();
+  } catch (err: any) {
+    console.error('API Error in updateExperiment:', err);
+    throw err;
   }
-
-  return response.json();
 };
 
 export const deleteExperiment = async (id: string): Promise<void> => {