Probably not actually. Transferring one kilobyte across a network link has such a low value that the billing costs of aggregating it cost more than the revenue.
So instead you take a probabilistic approach - charge the user for a megabyte of data transfer 0.1% of the time, and bill nothing 99.9% of the time.
Now the typical cost is the same, the users bill is probably accurate to the cent, but you have divided the number of billing records by 1000.
I don't know how cloud services count usage, but this is certainly not true for telco. I manage several fleets of hundreds/thousands of SIM cards (mostly IoT/M2M applications), and almost every provider counts the data traffic per byte. Different business and use case, I know, but still.
So instead you take a probabilistic approach - charge the user for a megabyte of data transfer 0.1% of the time, and bill nothing 99.9% of the time.
Now the typical cost is the same, the users bill is probably accurate to the cent, but you have divided the number of billing records by 1000.