Its very simple. The role of the HoT and the CFI may well be combined
You may well have a number of CFIs in an organisation, one for each department or role. CFI SEPL, CFI MEP , CFI Instructor courses, CFI IR, CFI Helicopter etc etc. The HOT has an overall responsibility. The HoT is not required to be a current and practicing Flight Instructor. but will have.been in the past. Another EASA construct. The ATO/DTO is required in its own construct to define these roles and responsibilities within its approval.
A paperwork exercise for most flying clubs so as TOO says, revert to the title that seems appropriate at the time.