Ron: Here's what I've been pondering. Offered for critique or criticism.
From an accounting standpoint, the funds are a loan from the bank, booked in the same manner as any other loan. So as long as that status remains, this is a loan payable on the books and the expenses are tax deductible. Forgiveness isn't guaranteed, so it's perfectly logical to retain it as a loan until forgiveness is certain.
Now if a taxpayer requests & receives forgiveness in the same year and the bank relies on the SBA reimbursement to forgive the loan, then the offsetting entry would negate the expense as you have described. But if the taxpayer waits until Jan 2021 to request forgiveness, then the adjustment to income (or expense, as you see fit), would occur in 2021. Nothing is certain until the loan is actually forgiven. Depending upon the taxpayer's circumstances, it might be desirable to shift the income into 2021. (I could spin out a few scenarios where this would be applicable but that isn't relevant to this conversation)
Now it's possible IRS may offer guidance on this before the end of the year. But it's a bit of an esoteric issue so they may not pay it much attention. In any event, this is my thinking right now given my understanding of the way this timing would impact a cash-basis taxpayer. It is somewhat similar to the tax treatment of a medical expense paid in 2020 and then reimbursed in 2021, at least in concept.