As a rule of thumb, the more aggressive the pedal signal correction, the more likely the driver will notice an impact on the driving experience. This is important because drivers (and especially employees) tend to respond to changes in a known acceleration rate by pressing the accelerator pedal further or accelerating for longer—which in turn chews into the original mileage gains.
The key is to maximize signal corrections without creating a noticeable change in the driving experience. For most commercial vehicles, trucks, and cars, this is mode 3 or 4.
If you do decide that you want to experiment with more aggressive modes, one of the best methods is to work up the ladder starting at Mode 3 or 4. Allow drivers to acclimatize in this mode for two weeks before bumping to the next mode. Then repeat this process until you reach your target mode. This process makes the overall large change less noticeable by dividing it into smaller adjustments distributed over weeks.
Sometimes the highest modes don’t necessarily produce the best results, depending on the vehicle and environment. The best practice is to experiment and track results for at least two weeks in each mode.