diff --git a/src/lib/ebus/data.cpp b/src/lib/ebus/data.cpp
index 03ff347c..859bbe97 100644
--- a/src/lib/ebus/data.cpp
+++ b/src/lib/ebus/data.cpp
@@ -274,10 +274,11 @@ result_t SingleDataField::create(const string id, const unsigned char length,
 			for (unsigned int i = 0; i < sizeof(dayNames) / sizeof(dayNames[0]); i++)
 				values[numType->getMinValue() + i] = dayNames[i];
 		}
+		result_t result = numType->derive(divisor, bitCount, numType);
+		if (result!=RESULT_OK) {
+			return result;
+		}
 		if (values.empty()) {
-			result_t result = numType->derive(divisor, bitCount, numType);
-			if (result!=RESULT_OK)
-				return result;
 			returnField = new SingleDataField(name, comment, unit, numType, partType, byteCount);
 			return RESULT_OK;
 		}
@@ -329,11 +330,11 @@ result_t SingleDataField::read(const PartType partType,
 	default:
 		return RESULT_ERR_INVALID_PART;
 	}
+	bool remainder = m_length==REMAIN_LEN && m_dataType->isAdjustableLength();
+	if (offset + (remainder?1:m_length) > data.size()) {
+		return RESULT_ERR_INVALID_POS;
+	}
 	if (isIgnored() || (fieldName != NULL && (m_name != fieldName || fieldIndex > 0))) {
-		bool remainder = m_length==REMAIN_LEN && m_dataType->isAdjustableLength();
-		if (!remainder && offset + m_length > data.size()) {
-			return RESULT_ERR_INVALID_POS;
-		}
 		return RESULT_EMPTY;
 	}
 	return m_dataType->readRawValue(data, offset, m_length, output);
@@ -358,11 +359,11 @@ result_t SingleDataField::read(const PartType partType,
 	default:
 		return RESULT_ERR_INVALID_PART;
 	}
+	bool remainder = m_length==REMAIN_LEN && m_dataType->isAdjustableLength();
+	if (offset + (remainder?1:m_length) > data.size()) {
+		return RESULT_ERR_INVALID_POS;
+	}
 	if (isIgnored() || (fieldName != NULL && (m_name != fieldName || fieldIndex > 0))) {
-		bool remainder = m_length==REMAIN_LEN && m_dataType->isAdjustableLength();
-		if (!remainder && offset + m_length > data.size()) {
-			return RESULT_ERR_INVALID_POS;
-		}
 		return RESULT_EMPTY;
 	}
 
@@ -502,7 +503,7 @@ bool SingleDataField::hasFullByteOffset(bool after)
 	}
 	NumberDataType* num = (NumberDataType*)m_dataType;
 	return (num->getBitCount() % 8) == 0
-		|| (after && num->getFirstBit() + (num->getBitCount() % 8) >= 8);
+	|| (after && num->getFirstBit() + (num->getBitCount() % 8) >= 8);
 }
 
 
diff --git a/src/lib/ebus/data.h b/src/lib/ebus/data.h
index 852ac472..3b2071c0 100644
--- a/src/lib/ebus/data.h
+++ b/src/lib/ebus/data.h
@@ -294,11 +294,11 @@ public:
 
 	/**
 	 * Get whether this field uses a full byte offset.
-	 * @param after @p true to check after consuming the bits, false to check before.
-	 * @return true if this field uses a full byte offset, false if this field
+	 * @param after @p true to check after consuming the bits, @p false to check before.
+	 * @return @p true if this field uses a full byte offset, @p false if this field
 	 * only consumes a part of a byte and a subsequent field may re-use the same offset.
 	 */
-	virtual bool hasFullByteOffset(bool after);
+	bool hasFullByteOffset(bool after);
 
 	// @copydoc
 	virtual void dump(ostream& output);