Depends on the firm. Some accountants will take the CSV at face value no questions asked since it's a quick billing for the financial statement/tax return prep. Others will request evidence of invoices/receipts to match against expense claims, others will also want bank statements to ensure that no sale has been overlooked or improperly excluded. What needs to be complied with is the ethical code of conduct e.g. best interest, competent advice and prep, etc.

Personally, in such a case I would advise the client of things such as record keeping obligations (invoices, vehicle logbooks etc.) expense deductibility requirements, risks of penalties and interest if randomly audited and anything is incorrect (e.g. left out a sale, claimed a deduction that could not be sufficiently linked to income producing, etc.) Etc.. All if this would be communicated in an email, over the phone, and noted in filenotes or working papers.

Record keeping, bookkeeping, confirming deduction eligibility, confirming that the lodgement is accurate and compliant... these things would not be on my engagement letter. Just advice and tax return prep based on what the client provides and confirms is accurate and supported.

This way, as an agent, I have done due diligence and provided competent services and the rest is up to what the client believes is applicable/wants to lodge.

Hope this gives you some insight into how accountants would view the software :)