Having watched this episode again, and assuming that Tosh wasn't locked up for over a year before Jack came to see her, I'll correct myself in saying that he may not have used Retcon on Owen because it didn't exist then. When Jack visited Tosh in the U.N.I.T. prison, he said that her mother wouldn't remember being kidnapped as he had given her a little pill that wiped it from her memory.
On another note, to pick up on the discrepancies with the established time-line, Jack may have briefly left TW to fight in World War 1, which may be why he didn't know more about Tommy from episode 3, or appear in the team photo from that time. I could, however, just be trying to tape over holes in causality
, which may be what the writers will have to do!
*okay, who damaged the time-line?*