If there will be both a wall mount oven and a surface unit, I would power them separately. Using a single OCP sounds like a great idea until the family gets invited over for a holiday dinner and supper is cooking on the range at the same time that the cake is baking in the oven.
I would not consider the 2 cooking appliances to be non-coincidental loads.
Even if this works right now for your family situation, what kind of problems are you setting up for whoever eventually buys your house down the road?