It has happened to me as well. For me it is purely psychological. Try doing one thing, load the car full, 2 in front 2 in back, then try to accelerate, you will instantly feel the difference, the surge will be back. Since you have driven 1000kms its more psychological than mechanical imo
. Only technical failures that i can think of is turbo leaking or oil overfilled after 1st service.
Its better to sit with the SA and ask him to connect the handheld to the obd scanner, then let him drive the way you do and monitor the boost pressure above 2k rpm it should cross 124kpa or higher, if it is in that range, then don't worry,enjoy ur ride ;) wish you many happy miles with ur ride.