Yeah, I work at a (much more legitimate) computer shop and we wouldn’t have up charged on that either. What we quote is what we quote, even if it blows out to 10 hours instead of 1, that’s on us not on the customer.
That computer shop my Dad went to, he learned afterwards from study mates that the shop had done that to multiple people for various different jobs, and they’re constantly changing names but I’m pretty sure it’s the same business running even today.