Marty Macfly
I'm not sure if I've understood the question, but my operator only allows selection of the next lesser flap setting upon reaching the minimum speed for the new setting.
An example: at 310t, Vref30 will equal approximately 160kts. Thus flaps 5 minimum speed will be 200 (VREF + 40), flaps 1 will be 220 (REF + 60) and flaps up will be 240 kts (REF + 80). While "cleaning up", flaps 5 are set passing 200, flaps 1 at 220 and flaps up at 240 (although above 307-ish tons, full maneuvering speed will only be achieved at Ref +100) .
Note that this is different from the classic where the +20/+40/+60/+80 are referenced to V2... on the -400 they're referenced to the Vref flap 30 speed for the current weight.