Hello Christina,
I have an idea, but I did not test it.
There is the enhancement project CCUX0000 with userexit EXIT_SAPLCUKO_001. The documentation says, the purpose of this userexit is to perform additional checks when leaving the configurator.
The internal function module CEI0_DDB_SET_VALUE_INTERNAL is able, to set an interval to a characteristic. The Input table of this function module is of type API_VALI. This structure has the following fields to handle intervals:
ATFLV lower value
ATFLB upper value
ATCOD value relation where 3 means the Intervall >= ATFLV and <= ATFLB
2 means the Intervall >= ATFLV and < ATFLB
Maybe you can use the the userexit EXIT_SAPLCUKO_001 to set the Intervall value via the function module CEI0_DDB_SET_VALUE_INTERNAL ...
