In fixing the compensation or damages to be paid for the condemnation of any property, the value of the property sought to be condemned with all improvements thereon shall be assessed, and if any of the improvements are separately owned, the value thereof shall be separately assessed. If the property sought to be condemned constitutes only a portion of a larger tract, the damages which will accrue to the portion not sought to be condemned by reason of its severance from the portion sought to be condemned, and the construction of the improvements in the manner proposed by the plaintiff shall also be assessed, and also how much the portion not sought to be condemned will be specifically benefited, if at all, by the construction of the improvement proposed by the plaintiff. If the benefit shall be equal to the amount of compensation assessed for the property taken, and for damages by reason of its severance from another portion of the same tract, then the owner shall be allowed no compensation, but if the benefits shall be less than the amount so assessed as damages or compensation, then the former shall be deducted from the latter and the remainder shall be the amount awarded as compensation or damages. In case of the exercise of the power of eminent domain by the city and county of Honolulu in furtherance of any governmental power under section 46-74.2 and the improvement ordinance of the city, the amount of damages or compensation assessed, or awarded, or agreed upon in any compromise approved by motion of the city council shall in no case be construed as limiting or affecting the power of the city council to distribute any portion of the cost upon any property found to be benefited thereby proportioned as provided by law in the exercise of their judgment whether under an improvement district or frontage improvement created before or after the acquisition of any such land. If condemnation is for the purpose of widening or realigning any existing highway or other public road, the owner of the property condemned shall be entitled to full compensation for the property actually taken and special benefits shall be considered only insofar as the value of the benefits shall not exceed the damages which will accrue to the portion not sought to be condemned by reason of its severance from the portion sought to be condemned and the construction of the improvements in the manner proposed by the plaintiff. That is, if the special benefits shall be equal to the severance damages, then the owner of the parcel shall be allowed no compensation except the value of the portion taken, but if the special benefits shall be less than the severance damages, then the former shall be deducted from the latter and the remainder shall be the only damages allowed in addition to the value of the land taken.