Advancing timing in close loop

In ecuflash is it ok to advance the timing in the close loop section in the base ignition tables?

It would probably help to mention which ECU / vehicle / engine you are using.

The answer to your question is probably what happens when you try this on the dyno in closed loop? (The only valid way to measure the result of an ignition timing change is to measure the torque and the dyno is the best tool for this.

Why do you want the advance the timing in that area of the map at all? The values that are there are most probably very close to be optimal from the OEM...sure you can probably improve on them for your specific application but being an OEM ecu that is not live tuneable, it would entail quite a bit of work and time for what probably is going to be minimal benefit