Hello Bhaskar,
In that case can you try doing Time Based Disaggregation for you Base Forecast Keyfigure.
Please maintain K (Based on another Key figure) in 'Time based Dis-aggregation' field and maintain your Key Figure KF1 in the 'Keyfigure for Time Based dis-aggregation' field.
Hope this helps you in your scenario.
Regards,
Anurag