Calculation rule of Up/down counter

Hi experts,

I was reading the LOGO version 8 siemens manual and faced with an uncertain text below about Calculation rule of Up/down counter (Page 178 in manual and highlighted in video I attached, by color cyan !! ): 

Note

So I can not understand the text above maybe because I do not know English well enough. First, that 900 pulses have been counted in one cycle? or generally?? Even I am not sure that the number 10000, for Off limit, is true or It must be 1000??! And I can not understand why it says "if the value Off= 980" ? Is it an example? why not another number?!!

But most important one for me is about that 10000!! Is it true 

I am completely confused!!  Heeellp!

Depending on th On and Off value there are different functions as described.

If the On threshold < Off threshold, then Q = 1, if On ≤ Cnt < Off

In the example On=950 and Off=10000. That means, the output is on in the range from 950 up to 9999. If you use Off=980 and a fast input is running between 950 and 980 in only one cylce, then the output stay off.

Regards, Scorp