It’s not even that, it was just an “Agreed-Upon Procedures” engagement. An assurance engagement would at least use a methodology the assessing firm would stand

It’s not even that, it was just an “Agreed-Upon Procedures” engagement. An assurance engagement would at least use a methodology the assessing firm would stand by on albeit with limitations. In this case, they don’t even claim the procedures are appropriate for how intended and unintended users might interpret the letter.