I cannot help You for the flats and sands....., I suppose you need really specific local charts
.....but if you change shallow depth to 2m , you will see one colour more ! dark blue for less than 2m.
in Uk and Netherlands
the depth contours in cm93 are 2, 5 and 10 meter.
this depth contours in cm93 are changing depending on the country, in Sweden
for example its 3, 6 and 10 meter!
so if you change country, it is advisable to check the depth contours and to change your settings.