Sort of feels like the Dutch Army has an unofficial stop line at the German Border(or a little farther at the Ems River) unless the British First Army is no more than a day behind them in getting to that level of advancement.
If this happens, it will tend to support Hitler's idea that the advancement in the north will stop and the area of concern is in the south. Not sure how obvious it is to the Germans which if the advancing armies in the north is Dutch and which are British.
That could work in the allies favour if the Germans assume the offensive is over and shift forces to where they feel the real threat is. A pause long enough to tempt the Germans into redeploying some of the defenders to other sectors and then hit them with everything you can hoping to breakthrough the weakened front line and into the German rear.