Even the most honest memoirist is reporting a subjective account. As we learned in my history classes, a memoir cannot be taken as a primary source for the events the author describes, only as a primary source for the author's interpretation of those events. It's always necessary to get supporting evidence from other sources rather than taking the contents of the memoir at face value.
So at best, A Stitch in Time tells us how Garak remembers the events of his life, not how they actually happened in detail. That's if he was trying to be as honest as possible. Even the best of us construct our memories into narratives reflecting our beliefs about ourselves and others, narratives that are more coherent and have more straightforward cause and effect than the reality probably did. We confuse our memories with other memories or imagined events, alter our memories over time, etc. And the further back in time an event is, the more unreliable the account becomes.
But this is Garak we're talking about, so yes, I do believe that his definition of truth is... situational. He will report events in a way that suits his goals. And I don't think he's above poetic embellishment just for the sake of art. Garak always treated lying as an art form.
There are a couple of points in particular where I'm more comfortable believing they're inaccurate or exaggerated accounts rather than literal reports. One is the description of Garak's experiences at the time of the Cardassian withdrawal from Bajor and Terok Nor, which clashes with the Millennium trilogy's depiction of those events. The other is something involving some sort of constellation that flickered in a certain way that was believed to be someone sending a message, something like that -- which doesn't make much astrophysical sense. I prefer to believe that was figurative, a myth that Garak was incorporating in his narrative for some symbolic reason.
