No. From what you just said JG (may I call you that? I have issues with people calling me WIE on other forums...), more surface area will increase the amount of bacteria. No, it will just spread them out more thinly, where they can be spread a little thicker. The bacteria population will stay the exact same, as long as the amount of food and the amount of oxygen is kept the same.
This is assuming the bacteria in that one basket of filter is sufficient enough to keep toxin levels safe.
More surface area can increase the bacteria if need be. For some reason I thought I read some where that he had a problem with his toxin levels.
If your have a heavy stocked tank or a large tank with a heavy bio load, one basket, which holds 1.8L of bio media, is probubly not going to be enough. Increasing volume of media can increase the amount of bacteria.
Now the truth of your statement is that if your bio capacity is sufficient for the bio load than adding more volume can just spread the bacteria out more.
This all depends on the amount of toxins coming out of the filter's output. If you find your toxin levels higher than zero coming out of the filter after its cycle period, than you don't have enough bio media volume.