Correct, this isn't a typo. Perhaps you should hold your one-off comments to a higher standard before you publish them.
The author mentioned they were having a few beers, I think we should give them a break. I understood what they were saying.
[0] Although you could argue that typo is an example of a minor mistake and used as such, making it a valid comparison.
400 a month is insanely cheap, 400 a week is insanely expensive. That completely changes the context.