Hi Boyington
I had replied to one of your posts on go around. The same logic applies in BUSS. In a go around Flap retraction of one step basically comes from flap full configuration landing where the drag is too much and is mandatory with flaps full. Flap 1,2,3 are takeoff configurations but you still retract one step to keep the procedure same. With unreliable speed and BUSS activated you are landing in flap3, would you risk stalling the aircraft just to follow a ritual of one step retraction? Just leave it as they are. With UAS you are not going anywhere just level off at circuit altitude and do another approach. At circuit altitude if you are uncomfortable retract to flap2 when speed is in the upper band. In any case you never retract to one unless overweight.