Different ratio for formula milk

Hi, i just switch from Nestle nanpro to Similac formula milk and noticed that the powder-water ratio is different. My LO is 1mth, and for Nestle they recommend 4 scoops to 120ml water, while Similac is 2 scoops to 60ml water? My nanny told me to just stick with 4 scoops even though im feeding Similac now.. is this right?