diff --git a/etl/eligibility/ha_15_32/ha_analysis_batch_3.py b/etl/eligibility/ha_15_32/ha_analysis_batch_3.py
index 8a46703e..0bf34e70 100644
--- a/etl/eligibility/ha_15_32/ha_analysis_batch_3.py
+++ b/etl/eligibility/ha_15_32/ha_analysis_batch_3.py
@@ -2841,6 +2841,9 @@ def forecast_remaining_sales(loader):
             eligiblity_counts, input_data, ha_ciga_conversion_rate, eco4_rate
         )
 
+        # Calculate the delta compared to Warmfront's original estimate
+        eco4_delta_vs_original_estimate = 200 * (eco4_post_ciga - original_warmfront_eco4) / original_warmfront_eco4
+
         eco4_post_ciga_remaining, eco4_post_ciga_remaining_revenue = calculate_eco4_post_ciga(
             eligiblity_counts_remaining, input_data, ha_ciga_conversion_rate, eco4_rate
         )
@@ -2862,14 +2865,17 @@ def forecast_remaining_sales(loader):
             ("ECO4 pre-ciga", "", "Remaining - #", ""): eco4_pre_ciga_remaining,
             ("ECO4 pre-ciga", "", "Total - £", ""): eco4_pre_ciga_revenue,
             ("ECO4 pre-ciga", "", "Remaining - £", ""): eco4_pre_ciga_remaining_revenue,
-            # ECO4 - asset list, post ciga
+            # ECO4 - asset list, post ciga, total
             ("ECO4 post-ciga", "", "Estimated total eligible - #", ""): eco4_post_ciga,
-            ("ECO4 post-ciga", "", "Estimated remaining eligible - #", ""): eco4_post_ciga_remaining,
             ("ECO4 post-ciga", "", "Estimated total eligible - £", ""): eco4_post_ciga_revenue,
+            ("ECO4 post-ciga", "", "Delta vs original estimate", ""): eco4_delta_vs_original_estimate,
+            # ECO4 - asset list, post ciga, remaining
+            ("ECO4 post-ciga", "", "Estimated remaining eligible - #", ""): eco4_post_ciga_remaining,
+            ("ECO4 post-ciga", "", "Estimated remaining total eligible - £", ""): eco4_post_ciga_remaining_revenue,
         }
 
         # Make sure nothing is forgotten due to duplicate multi-index keys
-        if len(to_append) != 14:
+        if len(to_append) != 18:
             raise ValueError("Something went wrong")
 
         results.append(to_append)