I think the bug and the cost were not that the cost was different at that time of day, but that by running at night without worry of interruption her script ran multiple times doing upload after upload after upload. If it had been during the day they would only have a few succeed because the line would get interrupted or couldn’t be used. Maybe during the day they’d only succeed on 3-5 calls but at night the script was making 50, 60, maybe even 70 calls.