Yes, if i understand correctly, Lets say the block needs X zeros to be solved and you be rewarded, for simplicity sake lets call this difficulty to solve a block is 100, so if your share has a difficult of 100 or bigger then you solve the block, your share having bigger than 100 difficulty also solves the block but you get no extra benefit. If you mine a share at 10 difficulty or 50 difficult it also does nothing as it doesnt solve a block, however since a pool is trying to pay for work done so luck (but you dont care about this). So lets say a pool set your difficulty to 10, this means shares with difficulty of 10 are counted as 1 share (worth 10 points), even if you manage to get a 100 or even 1000 difficulty share the pool will not give you more than 10 points. If your difficulty set by pool is 20 then shares mined under that will be deleted and every time you have a share with a difficulty bigger than 20 you get credit for 20 points exactly. Understood?