'Drift Over Time' but with easy-ease?

I'm using the nifty Adobe Drift Over Time preset. But its movement is linear. Any way to add an easy-ease to the start of it?

This is applied to the position property of the Transform plug-in:

driftDirection = degreesToRadians(effect("Drift Over Time")("Direction") - 90);
x_offset = Math.cos(driftDirection);
y_offset = Math.sin(driftDirection);
driftSpeed = effect("Drift Over Time")("Speed (pixels/second)");
[x_offset,y_offset] * driftSpeed * (time-inPoint)