diff --git a/las_outputs.py b/las_outputs.py
index 8e558c7..0e5ae36 100644
--- a/las_outputs.py
+++ b/las_outputs.py
@@ -178,13 +178,16 @@ def calculate_volumes(profile_name, survey_date, csv_output_dir, ch_limits, volu
     volumes.to_csv(csv_vol)
 
     # Get most recent volume difference for current profile
-    try:
-        previous_vol = volumes.loc[profile_name].values[-2]
-        current_vol = volumes.loc[profile_name].values[-1]
-        delta_vol = current_vol - previous_vol
-    except IndexError:
+    current_date_idx = volumes.columns.get_loc('Volume_' + survey_date)
+    previous_date_idx = current_date_idx - 1
+
+    if previous_date_idx < 0:
         # Return None if there is only one survey
         delta_vol = None
+    else:
+        previous_vol = volumes.loc[profile_name][previous_date_idx]
+        current_vol = volumes.loc[profile_name][current_date_idx]
+        delta_vol = current_vol - previous_vol
 
     return delta_vol
 
@@ -225,11 +228,17 @@ def process(yaml_file):
     las_data = call_lastools('lasclip', input=input_las, output='-stdout',
                              args=['-poly', crop_swash_poly], verbose=False)
 
+    las_name = 'crop-1.las'
+    with open (las_name, 'wb') as f:
+        f.write(las_data)
+
     # Apply sea-side clipping polygon
     print('Cropping back of beach...')
     las_data = call_lastools('lasclip', input=las_data, output='-stdout',
                              args=['-poly', crop_heatmap_poly], verbose=False)
 
+
+
     # Create clipping polygon for heatmap raster
     print('Creating heat map cropping polygon...')
     shp_name = os.path.join(output_poly_dir, las_basename + '.shp')