Rodney,
Although there's always some confusion about the actual sump capacity* but my understanding is that the manual says the fill capacity is 7.5L with an oil filter change - as per the Leeds service - although depending upon the drain time more oil could be necessary**, and the tech most probably won't have checked the level after filling with the standard 7.5L. I suspect that the Dealers always include (and charge you for!) a litre carton of Mobil 1 with every service so that you can top-up if necessary.
For reference, I think your Driver's Manual will say that Porsche considers an oil consumption up to 1.5L in 1000km as acceptable. On that basis it's possible that if the level was one or two segments down after the service and you've used about 1.0L in your 2,000 miles, which is acceptable according to Porsche, this has triggered the level warning. Each segment on the gauge is approximately 0.4L and if adding 1.0L has changed the display by 2-segments that sounds about right, so I'm sure the gauge is displaying correctly.
Jeff
* 10.1L dry apparently.
** Some US owners reckon that if they leave the oil to drain for 30mins or more the refill can be up to 8.5L. However, whichever way you look at it there could still be quite a lot of old oil swilling around after any oil and filter change.