The weather routing or departure planning will always use the highest resolution (1km,8km, 50km) and the most accurate GRIB files available. As the weather routing or departure planning is calculated on the PredictWind server, it is not dependent on what GRIB files you have downloaded, making the weather routing file size small, typically 10-12kb. The GRIB files are only used to visualize the routing, meaning the high-resolution GRIBS are not essential over a satellite connection.
If you notice a difference between the weather routing/departure planning tables data or cursor pop-up versus the GRIB overlay, this is most likely because you are reviewing likely 50km or 100km resolution GRIBS while the tables/pop-up are reporting the high-resolution 1km / 8km data.
Since the weather routing or departure planning is calculated on the PredictWind server, it is not dependent on what GRIB files you have specifically downloaded, making the planning and routing files highly accurate and a size small, typically 10-12kb. The GRIB files are only used to visualize the routing, meaning the high-resolution GRIBs are not essential, especially over a satellite connection.
If in doubt, put more weight on the departure planning tables. Since they are using the highest resolution data available, they are likely to be more accurate.