Resurfacing a long wasteboard

I am carving a 6 foot long piece of 1/4" neoprene rubber. I’ve gotten the machine to do what I want it to do but I am having a problem with two tiles matching in depth.

I will carve the first tile completely with three different pages. Two I use a 1/4" downward bit to carve multiple ribs in the rubber. The last I use a round over bit to round over the edges of the ribs.

The problem comes when I advance to the second tile. I use the same bits and depth settings but the second tile is about a 1/16" higher than the first tile. I redo do the second page and adjust the bit down to match the first tile but then the remaining material is thinner than the first tile.

I mount the piece of rubber on a 6 foot long piece of MDF using two sided carpenter tape which is very sticky. It holds rubber fine. I am thinking that the piece of MDF I am using might be slightly thicker on one end and would like to resurface the entire piece of MDF. Can I do a resurface using the tile feature? Resurface the MDF in two procedures?

that’s a pretty common issue, ensuring the wasteboard was recently surfaced and using planed stock (or stock that is of uniform thickness) and ensuring the surface of the stock is parallel to the spindle plane of movement will present the best starting point and typically correct, or nearly correct, that step issue you are experiencing.