In Formula Renault 3.5, if I list Rear ARB values in setup screen from softest to hardest using "+" button, I get not sequential values from small to large, but this confusing sequence: 10, 11, 14, 17, 18, 15, 16, 18, 21, 22, 19, 21, 25, 30, 31, 22, 24, 31, 38, 42, 29, 33, 45 , 61, 72 Also in LCD Pit Menu, Front Wing always set to be 2 clicks less than value set in Setup. For example, I have Front Wing set to 20 in setup, but when I go on track and look at LCD Pit Menu Front Wing is displayed at 18. If I make a pit stop, there is no change in Front Wing, so I think its may be just a representation bug.
I was also confused at first about the Rear ARB until I looked at the comments in the HDV. The first bar is a 20mm (Ø) x 2.25 (Wall thickness IIRC) Ti Blade, the next is 20x2.25 made of ?, the next 25x1.5, 30x1.5, and finally 30x5. So you'll need to hunt for which setting is best. It's not a bug. It is just organized in a fashion that is not apparent on a surface level.