It alluded to in SYS 70-90-40:
THRUST RATING MODE AND THRUST LIMIT VALUE
Indicates the thrust limit value and the associated thrust rating mode based on:
- The position of the thrust levers,
- Aircraft on ground or in flight,
- The engine status, i.e. running or not running,
- The data entered in the T.O and CLB panels of the FMS ACTIVE/PERF page.
The aircraft is on the ground, therefore it would need to takeoff before it can enter any other phases. There won’t be a FLX temperature set therefore all it knows is the TOGA value.