Account number range validation and numeric value validation not applied

Steps:

1. Install add on of Account range
2. Now go to configurations > Account
3. Now enter characters, special characters OR long numbers like 80 to 90 digit for Minimum Account Number & Maximum Account Number field.
4. Now save the record

Expected result : Account number range validation and numeric value validation should be applied on fields.

Actual result : Account number range validation and numeric value validation not applied on fields.