diff --git a/correios/models/posting.py b/correios/models/posting.py
index 4084e92..d5fb939 100644
--- a/correios/models/posting.py
+++ b/correios/models/posting.py
@@ -44,7 +44,6 @@
 MAX_CYLINDER_SIZE = 28
 INSURANCE_VALUE_THRESHOLD = Decimal("50.00")  # R$
 INSURANCE_PERCENTUAL_COST = Decimal("0.007")  # 0.7%
-MONEY_QUANTIZATION = Decimal("0.00")
 
 
 class EventStatus:
@@ -361,7 +360,7 @@ def calculate_insurance(cls,
         per_unit_value = Decimal(per_unit_value)
         if Service.get(service) == Service.get(SERVICE_PAC) and per_unit_value > INSURANCE_VALUE_THRESHOLD:
             value = (per_unit_value - INSURANCE_VALUE_THRESHOLD) * INSURANCE_PERCENTUAL_COST
-        return Decimal(value * quantity).quantize(MONEY_QUANTIZATION)
+        return to_decimal(value * quantity)
 
     @classmethod
     def validate(cls,
@@ -695,10 +694,6 @@ def __init__(self,
                  service: Union[Service, int],
                  error_code: Union[str, int],
                  error_message: str) -> None:
-        super().__init__(
-            service=service,
-            value=Decimal("0.00"),
-            delivery_time=timedelta(days=0),
-        )
+        super().__init__(service, 0, Decimal("0.00"))
         self.error_code = int(error_code)
         self.error_message = error_message
diff --git a/correios/utils.py b/correios/utils.py
index 10b7657..9fbcedf 100644
--- a/correios/utils.py
+++ b/correios/utils.py
@@ -69,13 +69,15 @@ def to_datetime(date: Union[datetime, str], fmt="%Y-%m-%d %H:%M:%S%z") -> dateti
     return date
 
 
-def to_decimal(value: Union[str, float], precision=2):
-    value = rreplace(str(value), ",", ".", 1)
-    if "." in value:
-        real, imag = value.rsplit(".", 1)
-    else:
-        real, imag = value, "0"
-    real = re.sub("[,._]", "", real)
+def to_decimal(value: Union[Decimal, str, float], precision=2):
+    if not isinstance(value, Decimal):
+        value = rreplace(str(value), ",", ".", 1)
+        if "." in value:
+            real, imag = value.rsplit(".", 1)
+        else:
+            real, imag = value, "0"
+        real = re.sub("[,._]", "", real)
+        value = Decimal("{}.{}".format(real, imag))
 
     quantize = Decimal("0." + "0" * precision)
-    return Decimal("{}.{}".format(real, imag)).quantize(quantize)
+    return value.quantize(quantize)