We really need a way of easily reporting on not just children who are currently On the Free School Meals (FSM) register, but also children who are Off Register (previously eligible) as these are counted as 'Ever 6' children which is a very common reporting group for state schools. An additional power bi measure containing all pupils from both these groups (On and Off Register, not Unassociated) would also be needed.
I can't currently see a way of achieving this with the options available.
Would us adding the below fields meet your requirements:
FSM Association
LAC Association
SEN Association
PP Association
SC Association