Hi,
the "normal" data structure is
yearly data - 0FISCPER3 = #
monthly data - 0FISCPER3 = 001 - 016.
you could use a rebook function to book your existing data from 0FISCPER3 = 012 to #.
afterwards, change your yearly aggregation level to one without 0FISCPER3, the data you will enter there will automatically be booked to 0FISCPER3 = # and monthly data will automatically be aggregated.
regards
Cornelia