Phoinix,
If you are in the AEO MCP (yellow band) for longer than 4 mins 55 seconds the LIMIT will illuminate along with a GONG at 5 minutes and you now have a recorded exceedance. In this case an MGB exceedance. Keep in mind that there are no sensors in the MGB to measure this limit. It is done by the engines via the FADEC.
There are 2 cases.
1) As soon as only 5 seconds of either 5 minute (AEO MCP) 2 minute OEI or 30 seconds OEI remain you will get a LIMIT with flashing box around it. If you exceed that limit the box goes to steady state with an audio GONG.
2) Exceedance of 30 second power OEI, 5 minute takeoff power (AEO Overtorque) or Mast Moment will trigger the LIMIT signal immediately together with a GONG. Depending on the exceedance it will be recorded. In the case of the AEO Overtorque there is a transient limit, check your applicable RFM as it varies between models.
Also keep in mind that AEO MCP is only useable at V less than or equal to Vy (65 KIAS).