IF_RSPLS_DS_METHODS~IS_PROTECTED & IS_OVERLAPPING not called

When testing an exit-based DS (Z-class inheriting from CL_RSPLS_DS_EXIT_BASE) with an input ready query (which works and display some previously saved data) in RSRT the following methods are called:

IF_RSPLS_DS_EXIT~GET_INSTANCE

IF_RSPLS_DATASLICE~CREATE_DATA_REF

CONSTRUCTOR

GET_INSTANCE_O

... but these methods are not called (despite being redefined):

IF_RSPLS_DS_METHODS~IS_PROTECTED

IF_RSPLS_DS_METHODS~IS_OVERLAPPING              

I have read the following:

Issue with user exit on Input enabled query

BI 7 - Data Slice with Exit Class

Any assistance is appreciated. Thank you.