(a) If, in the construction of sidewalks or making of other improvements, any owner of taxable property in a municipal improvement district shall be found to have improved his own property in such a manner that his improvement may be profitably made a part of the general improvement of the kind in the district, being also as good as that required by the system as determined by the board of improvement, the board shall appraise the value of the improvement made by the owner and shall allow its value as a setoff against the assessment against his property.
(b) In case the owner who has made these improvements shall be found to have failed to come up to the required standard, the board may allow him the value of the materials, so far as they may be profitably used in perfecting the system prescribed, as a setoff against his property thus improved.
(c) In these cases, the board shall issue to the owner a certificate showing the amount of setoff allowed, which shall be received by the collector in lieu of money for the amount enumerated and charged against the property.