Latency disappears?

Mucking about with the Demo of Sonar 5

I set the latency quite high (280mS "effective delay") and sure enough when I hit the Piano Rool "keyboard" I get the long delay.

Then I copy a simple track from an Audigy Soundfont played on the card, to a track that uses SFZ as its softsynth.

I use a PIano as its attack is nice and sharp, so you can hear the delay.

PLay each track solo to ensure that they are both playing. Then play bot tracks at once.

The first one, maybe two notes are delayed by maybe 20mS...then everything else is dead set on time.

Can somebody explain this to me?

Thank for any imput.

Nick