In those situations where the boundaries of a road improvement district embrace lands in more than one (1) county and any of the counties have available funds, either directly from the State Treasury or by action of the quorum court, to apply on the bonded indebtedness of road improvement districts in that county, the basis of ascertaining the proportion of the bonded indebtedness owing by the road improvement district that should be considered in allotting funds to road improvement districts in that county shall be the relation that the assessment of benefits in that county bears to the assessment of benefits in the road improvement district. The percentage that the assessment of such benefits in any of such counties is of the entire assessment of benefits in such district shall be the percentage of the bonds of such district entitled to allotments in that county.