Around my neck of the woods, at grassroots, same signal is used by ARs to let the refferee know "I need to talk to you".
It's an Australian mechanic - and taught in the Australian LOTG (we used to have some minor additions in the additional advice as well - I remember when 'shirts tucked in' was a requirement in the Australian LOTG but not the FIFA LOTG!@one Surely raised flag is first movement for 'I want to talk to you'. No idea where refs get half of these signals for that have never been in LOTG. Saw an assistant the other day playing an advantage. Baffling
To want to talk to ref, surely the universal method of raising flag and keeping it raised is preferred, accompanied by shouts of " insert name, come here please" and even using the other hand to indicate, come over.
On off chance ref is still oblivious to this, other AR if tuned in can raise flag, shout then point ref in other direction.