You are still governed by DOT HOS (Hours of Service). Package drivers are covered under the Short Haul Exemption. Staying within 150 air miles and working less than 14 hours. You are exempt from having to keep a record of duty status, log book or ELD. Your still bound by 11 hours drive time, 14 hours on duty (if driving) and 10 hours off. Package drivers rarely need to keep track of drive time, because 99.9% of the routes come nowhere near 11 hours actual drive time.
And your DOT violation? That could cost you and/or the company between $1,000 and $16,000 if the DOT found out. UPS does not report your hours, but if you were ever audited, pulled over, or snitched on...Good luck with that fine. Your sup only had your UPS hours of service. If you told him you team drove, for 3 full days and then only had 6 hours off, he wouldn't have let you work.
Let me take that back. Half the sups probably don't know what the HOS are, or would just overlook your hours because they needed you to drive. But, this sup would also be opening up UPS to that same $1,000 to $16,000 fine.
The DOT takes people like you, and/or your sup, that violate HOS very seriously. But ultimately, keeping track of your hours is your responsibility. And the fines are pretty hefty for a reason.