Many don't know this, but in New York, you do not have to post a labor rate. So, I don’t post it. All I am required to do is to let the public know how I calculate my labor prices. My sign in my customer waiting area states:
“Labor rate may be computed by either hourly rate, which is multiplied by clock hours and / or flat rate manual.
Most labor costs are charged by method of menu pricing only. E.g.: oil service, wheel alignment, wheel balance, tire mounting, or diagnostic analysis.
You, as the consumer, have the right to additional information and explanation on labor costs upon request.”
I don’t know what the laws are in your area, but my opinion is to get away from talking about time. Many of the jobs we do are menu prices and don’t fall into an hourly labor rate. For example: a brake job that takes you 30 minutes you may have a menu price for 1 hour.
To answer your question, having a number like $82.74 is harder to calculate, but do you really need that to avoid confrontation by the customer? There must be a better way.