Notwithstanding any other provision in this division, the legislative body may sell to any local, State or National public agency or authority authorized to purchase the same, all or any part of any bonds issued pursuant to the provisions of this part, or any bonds issued pursuant to the Improvement Bond Act of 1915, upon the security of assessments levied under this division. Any such bonds may be sold to any such public agency or authority without advertisement or bidding, but shall not be sold for less than par. The interest rate on such bonds shall be the rate fixed therefor by the legislative body, but may be for a lesser rate than that so fixed if the legislative body finds a purchaser at such lesser rate. Upon the sale of any such bonds to any such public agency or authority, the purchase price thereof shall be paid to the contractor or his assigns in lieu of the bonds and in satisfaction of the balance due upon the assessment.