That is my belief, but I may be wrong.

Another thing, there is a relation between the first two figures of tires (the second one is a percentage of the first one and gives the size of the tire wall).

Therefore, if you want to stay close to the circumference length of the OEM tire and allow the odometer do its job with not too much error, when one figure increases, the other has to decrease and vice versa.

Going 235/70R16 will put you way out of range and the odometer will give you false information. It should be more 235/60or65R16 and not 70, but you will need more calculation to know for sure.