Different rocker ratios intake vs exhaust

Pressure in the cylinder is about 100 psi when the exhaust valve opens. That makes things very different from the intake side, not to mention flow is going the other way.
The exhaust valve size is smaller, so to reach .35 times valve diameter for max flow comes at a lower lift. As compression rises, more time for the exhaust event occurs because preasure of combustion decreases much earlier allowing more exhaust duration.