The required improvements to be furnished and installed by the subdivider, which are listed and described above, are to be furnished and installed at the sole expense of the subdivider and at no expense to the city provided, however, that in the case of an improvement the cost of which would, by general policy of the city, be assessed only in part to the improved property and the remaining cost paid out of general tax levy, the City Council may make provision for payment of a portion of the cost by the city. If any improvement installed within the subdivision will be of substantial benefit to lands beyond the boundaries of the subdivision, the City Council may make provision for causing a portion of the cost of the improvement representing the benefit to such lands to be assessed against the same and in such case the subdivider will be required only to pay for such portions of the whole cost of the improvements as will represent the benefit to the property within the subdivision.
('72 Code, § 345:67)