Please help to understand Slash's Stat

[Fizpok]

Hi.
I am mining on Slash (mining.bitcoin.cz), with 2 workers / 2 video cards 5770.
I see, on GUI Miner: 746 accepted / 677 accepted, 191 / 191 MHash
I see, in the same time, in my mining.bitcoin.cz cabinet: Current shares 514 / 480, hashrate 67 MHash
It looks like they don't see / don't report part of my performance, am I right? What is going on?

[MashRinx]

Is the pool reporting the difference in shares as either invalid or stale (old shares still being sent for a previous block)?  That does seem odd, but I've never personally mined on Slush's pool, so I can't be any more specific as to the discrepancy.

[whitetoo]

I believe slower cards are prone to have inaccurate data on the stats, I think there is a note at the bottom of your account page stating so on the website?

[Fizpok]

I believe slower cards are prone to have inaccurate data on the stats, I think there is a note at the bottom of your account page stating so on the website?

Actually, the only column with star is correct...