cgminer must determine if a share (nonce) should be sent to the pool.
It would be really bad if it couldn't do that

When you tell cgminer you want all the extra information it can throw at you, by telling it '--verbose', one of the output lines is to tell you what it does with each nonce the chip returns to cgminer.
At 260GH/s you generate around 60 nonces per second.
My pool doesn't want you sending that much crap to it

Nor do you want to increase your network flow by 202 times

My pool will set a work difficulty so that you are sending shares at around 18 per minute.
Thus cgminer must work out what difficulty each nonce is and if it should send it.
In verbose more it tells you for, on average, 201 of those 202 that their difficulty is too low.
https://kano.is/index.php?k=workdiff