[33] It was next said that the preparation of the certificate for bill 3 was incorrect. The assessor's certificate for bill 3 was that the cost payable pursuant to the bill were assessed at $29,972.37, comprising professional fees of $20,407.12 and disbursements of $565.25. The professional fees were said to have been arrived at after deducting the costs of the assessment, assessed at $6,355.88 including the assessor's fees of $6,000, but even so on its face the certificate does not add up. Reference to the list of adjustments shows that, from professional fees claimed at $50,177.10, the total deducted of $23,414.10 left a balance of $26,763. The disbursements were claimed at $609.20, $43.70 was deducted, leaving a balance of $565.50 which balances the amount in the certificate. However, if one deducts from the professional fees the costs of the assessment as assessed by the assessor, one is left with $20,407.12. If to this one adds the disbursements of $565.25, the total is $20,972.37. The explanation for the certificate is therefore obvious enough: it contains a typing error, in that what ought to have been a "0" has come out as a "9". That is a ground for correcting the certificate, but does not justify any other relief.