diff --git a/deep_diff.py b/deep_diff.py
index fc30dfa..7a7eb4f 100644
--- a/deep_diff.py
+++ b/deep_diff.py
@@ -2,6 +2,7 @@ import json
 from copy import deepcopy
 from jay_diff import jay_diff_full, jay_merge_full
 
+
 def deep_diff(data, temp_data):
 	new_data = {}
 	for k in data.keys():
@@ -50,9 +51,9 @@ if __name__ == '__main__':
 				diffed_list = []
 				last = {}
 				for s in src:
-					diffed = jay_diff_full(last, s, combine_upd_add=diff_mode_update_add)
 					print(f"Old: {last}")
 					print(f"New: {s}")
+					diffed = jay_diff_full(last, s, combine_upd_add=diff_mode_update_add)
 					print(f"Diffed: {diffed}")
 					diffed_list.append(deepcopy(diffed))
 					last = deepcopy(s)
@@ -60,9 +61,9 @@ if __name__ == '__main__':
 				merged_list = []
 				last = {}
 				for d in diffed_list:
-					merged = jay_merge_full(last, d)
 					print(f"Old: {last}")
 					print(f"Diff: {d}")
+					merged = jay_merge_full(last, d)
 					print(f"Merged: {merged}")
 					last = deepcopy(merged)
 					merged_list.append(deepcopy(merged))
diff --git a/jay_diff.py b/jay_diff.py
index 7d5715a..bfcef0f 100644
--- a/jay_diff.py
+++ b/jay_diff.py
@@ -84,10 +84,11 @@ def jay_merge_update(_old, _new):
 def jay_merge_add(_old, _new):
 	for k, v in _new.items():
 		if isinstance(v, dict):
+			r = jay_merge_add(_old.get(k, {}), v)
 			if k in _old:
-				_old[k].update(v)
+				_old[k].update(r)
 			else:
-				_old[k] = v
+				_old[k] = r
 		else:
 			_old[k] = _new[k]
 	return _old
@@ -539,3 +540,29 @@ if __name__ == '__main__':
 	result = jay_merge_full({}, {'add': {'a': 'hamburger', 'b': 'fries', 'c': {'e': 'coke', 'f': 'coffee'}}})
 	assert result == {'a': 'hamburger', 'b': 'fries', 'c': {'e': 'coke', 'f': 'coffee'}}
 
+	result = jay_merge_full({}, {'add': {'a': 'hamburger', 'b': 'fries', 'c': {'e': 'coke', 'f': {'coffee': {'h': 'black'}}}}})
+	assert result == {'a': 'hamburger', 'b': 'fries', 'c': {'e': 'coke', 'f': {'coffee': {'h': 'black'}}}}
+
+	result = jay_merge_full({'a': 'hamburger', 'b': 'fries', 'c': {'e': 'coke', 'f': {'coffee': {'h': 'black'}}}}, {'add': {'c': {'f': {'coffee': {'j': 'sugar'}}}}})
+	assert result == {'a': 'hamburger', 'b': 'fries', 'c': {'e': 'coke', 'f': {'coffee': {'h': 'black', 'j': 'sugar'}}}}
+
+	old = {'charging': {
+		'batteryStatus': {'value': {'carCapturedTimestamp': '2024-10-19T05:34:34Z', 'cruisingRangeElectric_km': 192}},
+		'chargingStatus': {'value': {'carCapturedTimestamp': '2024-10-19T05:34:34Z'}},
+		'chargingSettings': {'value': {'carCapturedTimestamp': '2024-10-19T05:34:30Z'}},
+		'plugStatus': {'value': {'carCapturedTimestamp': '2024-10-19T05:34:29Z'}}}}
+	update = {'charging': {
+		'batteryStatus': {'value': {'carCapturedTimestamp': '2024-10-19T05:35:46Z', 'cruisingRangeElectric_km': 191}},
+		'chargingStatus': {'value': {'carCapturedTimestamp': '2024-10-19T05:35:46Z'}}}}
+	add = {'charging': {
+		'batteryStatus': {'value': {'currentSOC_pct': 55}}},
+		'fuelStatus': {'rangeStatus': {'value': {'primaryEngine': {'currentSOC_pct': 55}}}},
+		'measurements': {'fuelLevelStatus': {'value': {'currentSOC_pct': 55}}}}
+
+	delete = {'charging': {
+		'chargingSettings': {'value': {'carCapturedTimestamp': '2024-10-19T05:34:30Z'}},
+		'plugStatus': {'value': {'carCapturedTimestamp': '2024-10-19T05:34:29Z'}}}}
+
+	result = jay_merge_full(old, {'update':update, 'add':add, 'delete':delete})
+	assert result == old
+