When you are fit for a bike, where the seat is ultimately positioned is NOT taken into account for frame size.

So your new seat position forces you forward a bit more. Who cares? Its when you RIDE your bike that the distances, angles, and positions matter. You're no longer standing where you used to when straddling the bike. Unless you foresee this being an ongoing problem (i.e., you stand over you bike a lot and don't find a comfortable easy way to angle it or whatnot at stopsigns or traffic lights), just let it go and enjoy your newly positioned seat!

(FWIW, I'm not surprised that he nudged it forward when he raised the seat; additional height usually means a few mm or more of backwards position for the seat and to get your foot centered over the pedal correctly you need to adjust the seat forward as well.)