Accuracy

A total is only worth what the lines under it are worth

The scan reads an image. Images are imperfect, and so is reading them.

It can misread a price

A cramped line, an unusual currency format, a screenshot taken at an angle. The amount comes out wrong and the total inherits it.

It can miss an entry

Anything scrolled off the bottom of the screen was never in the frame. This is the single most common gap, and the reason several screenshots beat one.

It can include something that is not a subscription

A one-off purchase sitting among the recurring ones looks the same to a reader that only sees the image.

All three are corrected the same way: edit the line, delete it, or add the one that is missing. The monthly and yearly figures recalculate from your version, not from the scan's.