By asking a CPU Miner (or any miner that isn't at least some X% of the network's total power) to process the entire getwork solution space before performing another GetWork, you are dooming that Miner to a very significant percentage of Stale shares.
Potentially stale to the network, yes... to the pool, not always.
To that degree though, you could technically say that any miner who has not solved a block for the pool is not benefiting the pool. We tend to disagree, and thats why we credit equally across the board. A submitted share is a submitted share.
That's not what the OP says:
- Anti-fraud protection. We only accept shares from the current block, in the current round.
FairUser said that submitted shares are only accepted from the current block within the current round.
If you want to change this to just within the current round (what you are implying), then the Solution Rate variable for the Stale Rate computation would be based on the Pool's Solution Rate as opposed to the Network's Solution Rate.