I've been tracking this second transfer and I've discovered that was done with another addres. The first payment that I've sent you today create a new "change account" with the reamining btcs, and that was then used for the second payment. I didn't know that bitcoin-qt could do that. You can see it in the initial transaction

0437846789953f2d6520f6f85430d724bb91f57467677ab8ac917e223bb30fd0 2013-05-21 11:53:42

169aGEDiYyQST13J5doPnzSH2N9zQycapV --> 12o8iQqAve6yN6QnjhVg1yuaASb66jPJhs 2.592 BTC
                                                              185um4LMbmv5Gfr6zx6p56FdShibuxA8ro 3.838 BTC

And the transaction with the second payment is
5ab046a7c0b94ce32197e4fa634ad5ad2def305a20c7d9060a22b04a23b848ca 2013-05-21 18:02:31
185um4LMbmv5Gfr6zx6p56FdShibuxA8ro --> 12o8iQqAve6yN6QnjhVg1yuaASb66jPJhs 2.592 BTC
                                                            16W4QCCrhuUNynbcX2zAFyYVqZySq66Peh 1.246 BTC
The problem is that I have no control of these "change account".
Please T13hydra, Could you confirm that you received all payments and group the two orders for the initial 169aGEDiYyQST13J5doPnzSH2N9zQycapV address.
Thanks in advance.