[buddydvd]

You mean 37 pixels?

(640-(4*114))/5 = 36.8 pixels.

I wonder why they didn't choose this instead:

38+36+36+36+38

That would be most evenly spaced, symmetrical, and compatible with non-retina displays.

[sirn]

App titles. You can have less margin on the edge since you don't have to considers the app title length from the other side.

[buddydvd]

Ah, that makes perfect sense.

I guess, this would be pointless:

36+38+36+38+36 (18+19+18+19+18)

since the 2nd and 3rd icon wouldn't get the benefit of the extra spacing.

So the reasonable option would be: 34+38+40+38+34 (17+19+20+19+17)