I don’t really understand why 30 000 objects need 3000 selects and 3000 updates, do you think that these numbers are arbitrary? Ie. Could they have used 30 000 selects and 30 000 updates?

I found this at http://polepos.sourceforge.net/results/PolePositionClientServer.pdf
As far as my understanding goes, the objective behind choosing a number while doing benchmarking is a rather big number . It has an advantage that a program will execute for a measurable amount of time. If the number is too slow like 100 updates then the execution time will be in mili seconds and will be extremely difficult to bench mark them.