Is there a reason to not grate cheese ahead of time?
You should only grate cheese as needed, particularly the cheeses you mention.  When you grate cheese you create more surface area.  That is more surface exposed to air and oxidation, which will degrade the flavor and aroma of the cheese.  It is also more prone to drying out further degrading the quality.   The cheeses you mention are best when grated for immediate use, but stored in chunks, wrapped and refrigerated.