A title change does NOT exempt the employer from having to pay you overtime. All work you do for the same employer, regardless of what that work is or the title you do it under is counted together for overtime. However, note that in your state (CO), the law only requires overtime for working more than 12 hours in a single day (not 8) or more than 40 hours per workweek. (I have included a link below to a webpage put out by your state's dept. of labor about overtime.) If your employer was paying you overtime after 8 hours of work, it was voluntary for it to do so--the law didn't require it. That means they could choose to not pay you overtime after 8 hours, but only to pay it when the law requires (after 12 hours per day, or 40 hours per week).