When we complete waiver for our customers, should we include the sales tax in the amount of payment being received? Our company is completing/signing the waiver prior to processing the billings not after the invoices have been billed in our system, so we are unware if they are taxable and if taxable the amount the taxes will be. This would be for Arizona, New Mexico, Utah, Idaho, Texas, California, Nevada, Colorado, Wyoming and Oklahoma - where job are gross receipts or sales tax with no valid tax exemption on file.
Lien waiver amounts should match the amount on the check that's being received in exchange for the lien waiver. That being said, relatively minor discrepancies between the check and the waiver likely shouldn't be a huge problem (though waiver recipients, lenders, and property owners will typically want the figures to match up pretty well).
It's also worth mentioning that the only party who will really ever challenge the validity of a lien waiver is actually the person submitting the waiver. After all, why would a lien waiver recipient want to invalidate a waiver they've been given? So, if the customer accepts the lien waiver that's submitted, that's ultimately what matters most.