Hi,
Please note that this number range is defined at MM node instead of FI, hence you are requested to take into consideration the inputs from MM consultants as well.
There is no major impact is that the series will be different will cause loss of continuous numbers. In case you are defining for 2015, you will have to maintain each year so duplication of .numbers across fiscal year. In this case you will need to change logic in Z developments made by you and add fiscal year (GJAHR).
Regards,
Tejas