[processing] suggests to use different parameters with resampling in SAGA and to use the highest resolution when using SAGA raster calculator

When using SAGA mapcalc, why using the lowest among the inputs resolutions? Maybe SAGA gui does it by defaul? it does not seems necessary nor mandatory. 

SAGA also uses by default BSpline when doing a resample operation, the suggestion is to use NN.

This way the result of a SAGA mapcalc operation is identical to the ones obtained with QGIS raster calculator.