• Waiver of lien rights in a contract prior to commencement of work should be considered valid in the absence of case law.
• Implied waivers by subcontractors based on pay-if-paid terms are presumably invalid for lack of clear and unequivocal waiver in the absence of case law.
• The scope of lien waivers are also broad.  A lien waiver or release waives ALL lien rights of claimant as to the particular improvement to which the waiver relates, unless the waiver is specifically limited to a particular lien right or portion of the services or materials furnished.
• "Paid if Paid" is enforced if explicit.
• "Pay when Paid" suggests time for payment.
• Pay-when-paid and Paid if Paid clauses in the subcontract or purchase order do not create a condition precedent to payment.

Retainage Provisions

Public

• There are no statutes specifying the maximum or mandatory rate of retainage.  For state highway system roads and bridges contracts, if the contractor has provided all required reports and has not been paid, the department shall pay to the contractor interest at a rate three percentage points (3 percent) above the previous year's average annual Federal Reserve composite prime lending rate on the amount retained and on the final payment due the contractor beginning sixty days after final completion of the work and running until the date when payment is tendered to the contractor. NEB. REV. STAT. § 39-1349.

Private

• When work has been performed pursuant to a contract, a party may only withhold
  payment for retainage, in an amount not to exceed the amount specified in the contract, if
  applicable, until the work is substantially complete. Neb. Rev. Stat. § 45-1204.