Did your mechanic check the level? Who changed the fluid (this is a Vibe right?); the dealer or you? Is this "Castrol Syntorq" the same colour as the stock fluid?
To answer you question, who can say? It will certainly torture you if you do risk it. What you would need to do is take along a jack, wrench and filler thingy and check it when you get where you are going.
Just to kick you when your down

is this not a Toyota tranny? Why did you trust GM to give proper instructions on something they didn't design. GM installs dexcool in Honda powered Vues.

They are an insane company where one part of GM has no control or knowledge of what other parts do. I certainly hope that nobody at the Vibe dealer clues in on your tranny fluid change.
What does Toyota recommend as a synthetic alternative for the Matrix 5 speed?