A surprising amount of small business time still goes into moving numbers from paper into a computer. Supplier invoices arrive as paper or as an image attached to an email. Receipts accumulate in a wallet or a glovebox. Delivery notes come on a pad. Somebody, usually the owner and usually in the evening, sits down and types the figures into the accounts. It is work that creates nothing - the numbers already exist, they are simply in the wrong form - and it is work that nobody enjoys, which is why it is postponed, which is why it eventually happens in a large unpleasant batch just before a deadline.
Machine reading of documents has become genuinely reliable for this, and the reason it is worth revisiting is that it used to be poor. The older generation of scanning tools worked on clean, predictable layouts and fell apart on a creased thermal receipt or an invoice laid out in an unfamiliar way. Current tools handle a photograph taken on a phone, at an angle, of a crumpled receipt, and will identify the supplier, the date, the total and the tax amounts without being told where on the page to look. Anyone who tried this some years ago and concluded it did not work should try it again, because the thing they tested is not the thing that exists now.
The condition is about the shape of the errors rather than their frequency, and it is the part worth understanding. When a person mistypes a figure, the result is usually obviously wrong - a decimal point in the wrong place, a transposed pair of digits producing an implausible total - and it gets caught because it looks strange. When a machine misreads a figure, the result is usually plausible: an eight read as a three, a total read correctly but attributed to the wrong supplier, a date read as the invoice date when it was the delivery date. Plausible errors do not announce themselves, and they survive the casual glance that catches the obvious ones.
This points to a specific and cheap check rather than a general instruction to be careful, which nobody can act on. Check the totals against what was actually paid, because the bank statement is an independent record and a misread total will not match it. Check that the supplier is right, since a misattributed invoice is the error that causes the most confusion later and is the easiest to spot at the time. Everything else - line items, descriptions, reference numbers - matters less and can be left to the occasional review. Done that way, an evening of typing becomes twenty minutes of checking, and the checking is the part that was always worth a person's attention.