Old man - No you are not maxing out the 3.3 V Rail. Voltage drops as you approach Max Current, Not increase.
As Nuke Master said the ONLY true verification is to measure the voltage with a Multimeter. This should be done under load, Not with the 20/24 pin connector disconnected.
ONLY recommend if confortable doing!
The best/safest way to to this is to remove the MB and lay it flat on a table. Connect the monitor - Do not need to connect FDD, HDD of Optical Disk. You only need to have system power on to bios.
Insert the neg lead from the Multimeter in to a Molex grn (Black).
Insert a straight Pin into the 3.3 socket where the wire goes into the plug. Power on, Measure, power off. Should be between 3.2 to 3.4 Volts. Say it measured 3.35, You then know to add/subtract the difference to reading in Bios, also if correct you know to ignore Asus probe.
ADDED - Just saw nuke's last post - Concur, You should be fine, One minor difference, the 3.3 V is primary supply for low voltage Processores.