It's almost funny. The B737 FCTM has the following two sentences about the scenario discussed, that GSmini is supposed to handle:
When using the autothrottle, position command speed to VREF+5 knots. Sufficient wind and gust protection is available with the autothrottle connected because the autothrottle is designed to adjust thrust rapidly when the airspeed drops below commanded speed while reducing thrust slowly when the airspeed exceeds commanded speed. In turbulence, the result is that average thrust is higher then necessary to maintain command speed. This results in an average speed exceeding command speed.
That's it folks, Vref+5
