About this statement:
"Projects located where standard supply pressure is different than the LEED baseline supply pressure may calculate the water consumption of flow fixtures and fittings at the local standard supply pressure; the supply pressure must be consistent in the baseline and proposed case."
Because this is the case in Portugal (standard 3 bar), I would go for this approach, but the second part of the statment seems to indicate that we should compare this value with the baseline, at the same pressure. So should we adjust the values of the baseline flow rates in the calculator considering the same pressure, and if so, how? Or should we just compare the baseline values at a pressure of 415 kPa with the proposed values at a pressure of 300 kPa?