Why is it that the numbers in the censuses taken in the desert always contain round numbers? Generally speaking, with the only exception being Gad, all the numbers seem to be rounded to the hundreds, and even Gad is rounded to fifty. (Bamidbar 1:24)

Especially in light of the fact that there are many commentators that say that the significance of the count was to demonstrate the importance of each individual, why would the verse then seemingly omit many of them?

Any sources that address this issue would be appreciated.