That is not how it works. The laptop will pull as many amps as it wants from the power supply. If the power supply is rated at 2 amps and the laptop draws 4 amps the power supply will overheat and burn out in its attempt to provide 4 amps to the laptop.
The rating on the laptop is for max current draw (charging while using the computer). If you charge the battery with the computer off or use the computer with the battery removed the current draw will be less. How much less I don't know.