After looking at what constitutes a "custom add-on," it seems Bench is prohibitively expensive for anything but the most simple businesses. Here is what they say are "common examples" of a custom add-on:

  - Payroll reconciliation for W2
  - Multiple revenue streams
  - Employee reimbursements
  - Loans and lines of credit

Yeah we'd need all four of those which immediately puts us into the "Enterprise" bracket, which is about $600/year more than we pay our current accountant (who has a local office and many staff so they should theoretically be more expensive than Bench no matter what).