Though I'm not familiar with the various Acronyms, I assume they're some sort of accounting/costing discipline.
Many years ago a friend went to work for a main agent garage....because there was no carpark, he would be assigned a job-card and keys to the vehicle.....scour the streets, extract the vehicle, drive to workshop and park in bay...go to stores and wait for parts/products/finish job, tour streets park, return and clock -off the job.
" How can I make a bonus when I get 1/2 hour to fill-in Antifreeze and it takes that to get it into the Bay? "
The customer paid the "book" time....the rest was reflected in the chargeout rate.
When u had my own business, I was lucky to charge more than 40% of the hours I worked.....but i didn't charge a fiver for slipping in a new sidelight bulb either!
The headline hourly rate is, therefore, meaningless...the quality of work, diligence of the operative and total bill is what counts.
A high headline rate tends to scare -off the petty quibblers and tightwads you get left with a core of good, reliable customers who are willing to listen and pay a fair price.