So I let it run for about an hour and it has added transactions up to the 2nd of June, the balance also reflecting that amount. I had since withdrew these coins. When it is all caught up there should be 10 BTC in there, right now it reads that i have 21 BTC. I assume once it catches up to the point where i withdrew this that will go away, but what would happen if i try and sent 10 BTC to mtgox before it catches up to the 10 I should actually have.
Your transaction would be rejected by the network as a double-spend.