Such option is not supported with the Alexa skill as of yet but there are plan to do so.
You will have to invert the semantic extension settings of the actual metadata configuration associated with blind metadata label. It’s the not the cleanest but this is the only solution currently.
Rollershutter Blind "Blind" {alexa="RangeController.rangeValue" [category="INTERIOR_BLIND", friendlyNames="@Setting.Opening", supportedRange="0:100:10", unitOfMeasure="Percent", actionMappings="Close=100,Open=0,Lower=(+10),Raise=(-10)", stateMappings="Closed=100,Open=0:99"]}