The contractor shall furnish satisfactory evidence that the subcontractor had workers' compensation insurance in force covering the work performed for the contractor. For each subcontractor for which such evidence is not furnished, additional premium shall be charged on the policy which insured the contractor as follows:

The contractor shall provide a complete payroll record of the employees of each uninsured subcontractor. Premium on such payroll shall be based on the classifications which would have applied if the employees of the subcontractor had been employees of the contractor.
If the contractor does not supply the payroll records of its subcontractor, the full subcontract price of the work performed during the policy period by the subcontractor shall be established as the payroll of the subcontractor's employees. The additional premium shall be charged on that amount as payroll. Exception: If investigation on a specific job discloses that a definite amount of the subcontract price represents payroll, such amount shall be the payroll for the additional premium computation. In contracts for: (1) mobile equipment with operators (such as but not limited to: earth movers, graders, bulldozers, or log skidders), the payroll shall not be less than 33% of the subcontract price, (2) labor and material, the payroll shall not be less than 50% of the subcontract price, (3) labor only, the payroll shall be established as not less than 90% of the subcontract price.
If an experience modification has been established for the contractor, such experience modification shall be applied to the premium developed for the uninsured subcontractor.