Default materials cost

LEED default materials cost is 45% of total construction costs (based on specific Master Format divisions). What if in a given country we know that materials costs constitute a much higher part in the total construction costs and can be equal to even around 60-70%? Should we still use the default of 45% or should we use our own assumption which is more strict? In other words can we estimate and increase the default value from 45% to e.g. 70% so LEED documentation is more accurate? The project group doen't want to use the actual material cost option due to the size and complexity of the project.