"The user can delete or void a single bill as needed"
Can and Should are completely different concepts.
If you filed taxes on the year in question on Accrual Basis, everything is Double-entered and double-reported. If you filed on Cash Basis, but what is entered on Bills hits another balance sheet account, they Still Show, as well, so Checksfor what also is on a bill = Double-data entered. That's why you don't Void or delete a historic period.
Even offseting with Current dates might not the right way to do it. Example: If this is only the previous year or two, your CPA can help you determine if fixing the data for its original date is proper, because your entity will file Amended Returns.
And even if this in not a Tax issue, if that affected, as one example, Inventory, then it is likely someone made correcting or offsetting entries such as Adjusting inventory because, oh, look! We seem to show Twice as much stuff as we ever bought.
Any transaction can be Void or Deleted or Offset. Knowing which is the Right Task to do ineach case, isn't something anyone can answer without being able to see the info and be involved in what else it affects.
Auditors use a term: Material, as in, "Is it a large enough mistake to be Material to the financial reporting as that is, now?"