The simple answer here, is that you are simply wrong. No one in IE is trying to force drivers to work off the clock. The allowances for most routes are very challenging. And yes, many of them do not take into account a ton of issues drivers face on many routes and are simply not a good indicator of how well someone should do on that route. Some are the opposite and are too easy. But none of that is the point.
The whole idea of the system is to hold everyone to a very high standard, to get the most possible out of the drivers all the time. Period. How does not enter into it. If a driver chooses to work through lunch as the solution to looking better on paper, that is that drivers choice, and has nothing to do with the IE department. Nothing. Now, if a driver works to his fullest potential, safely and efficiently every day, and still looks bad on paper, who the hell cares? When the sup gets on car with him, his performance will not change one bit. So he gets a lock in ride, and afterward his performance does not change. Unless you are having a time study ride, when you are out there delivering there is no IE standing next to you. You are an adult and a highly compensated professional, you should take responsibility for your own decisions.
By the way, it has been my experience that most drivers who work through their lunch and break do not do so in order to look better for the IE department. They do so because they want to get home to their families that much sooner. In the old days, that was perfectly fine with UPS, including the IE department. It was the courts and the union that said we MUST force drivers to take a lunch.