When any improvement is authorized for which assessments may be made against the abutting landowners, the governing body may, before the amount to be finally assessed against or apportioned to each landowner or fixed by agreement is determined, cause to be recorded in the deed book of the circuit court clerk’s office for such locality, an abstract of the resolution or ordinance authorizing such improvement showing the ownership and location of the property to be affected by the proposed improvement and the estimated amount that will be assessed against or apportioned to each landowner or fixed by agreement with him and the same shall be indexed in the name of the owner of the property. Such assessment shall be a lien solely on the abutting land as provided in § 15.2-2411. After the completion of the improvement, the estimated amount shall be amended to show the amount finally assessed against or apportioned to each landowner or fixed by agreement with him, which final amount shall in no event exceed the estimated amount for the improvements as initially authorized. The amount finally assessed against or apportioned to each landowner may be greater than the initially assessed amount when the increased amount is for additional work being performed when the work was requested by the landowner and the additional work and its estimated amount is written into a separate agreement between the locality and the affected landowner. From the time of the docketing of such abstract, any purchaser of, or creditor acquiring a lien on, any of the property described therein shall be deemed to have had notice of the proposed assessment.