So I have been employed by UPS for close to 6 years, first two months on unload, moved to sort aisle and have been there ever since. I recently checked my hubs seniority list and noticed that I was marked as unskilled, everyone else on the sort aisle is marked as a skilled employee. I addressed this with my supervisor and he changed my pay status in the computer system. After the change I received a $1 raise. If I were to file a grievance, is it possible for me to get back pay for all of the time they underpaid me?