This calculation is an extension of the angular response example. In addition to varying the angle of incidence, we change the position of the microlens array relative to the rest of the pixel. Notice the offset position of the microlens array in the following screenshot.
Shifting the microlens position makes it possible to get higher optical efficiencies at non-normal incidence. Microlens (and other comonents) shifts are typically used to improve the efficiency of pixels near the edge of the array when the chief ray angle is not at normal incidence.