What will be infected if set CAD check interval with different time

I am newbie on Radio, and just use LoRa module as a black box.
I know the interval to active CAD should less than (Npreamble - 2)*Tsymble. But the value calculated acording to datasheet is too big for my case, it getting relatively stable after I decreased it to 50%. I don’t know if I calculated wrong.
What my question is: what happens if I set the value far small, 1ms against calculated 5ms,e.g.