That thread did not answer the question.
Page 225 "Dismounting" states: "An infantry unit may
not move or make attacks in the same turn that it dismounts."
The quoted thread offers as an answer page 224 "Mounting": "Mounted infantry may not fire weapons, spot for indirect
fire or take any action other than dismounting from the carrier."
However, the infantry who have dismounted are no longer mounting a carrier unit.
Page 111 "LRM Indirect Fire" stipulates: "In order
to serve as a spotter, the unit must not have charged or launched a
Death From Above attack that turn."
The Indirect Fire rules restriction on spotting does not include infantry units who have disembarked, nor does it stipulate that the spotting unit must be able to make attacks, nor does it define spotting for indirect fire as an attack.
