GST classification for rab: reduced rate for pre-packaged labelled sales and nil for other sales; past-period regularisation applied. GST classification for rab distinguishes supplies by packing and labelling: pre-packaged and labelled rab attracts a positive GST rate, while rab sold otherwise is nil-rated; the distinction takes effect from the notified date, and past-period treatment is regularized on an 'as is' basis to resolve divergent interpretations.