Deck blocks for floating deck

I am building a low level floating deck using deck blocks and to line it up with an existing attached deck I have to dig the deck blocks into the ground about 5 inches.
I would like to minimize any heaving in the winter and my thought was to put about 4 inches of gravel underneath them and then an inch of leveling sand to help get the water away.
Is this overkill since they are designed just to basically sit on the ground?