The value you put in is the sort of the frequency. If I set a value of 100 data is saved every time the number of time steps is divisible by 100: not every 100 time steps from when I set the value in the panel.
So, using the 100 example. If I set at 99 time steps I get an auto save almost immediately (at time step 100). If I set at time step 101 I have to wait 99 steps for 200.