Okay, let me see if I can give some info.
I will use Sriver as an example. Regular Sriver has the same topsheet as Sriver FX but the sponge on FX is softer. So the hardness of the topsheet does not always change with the hardness of the sponge.
On rubbers like DHS there is a thought that the red rubbers are not quite as good as the Black rubbers. From a technical standpoint the color of the topsheet should not change the quality of the rubber because the only difference should be the color of the dye used. However, it is possible that the red topsheets for DHS are made slightly differently for one reason or another so that the Black ones do in fact work better. I have felt no real difference between red and black myself. But....
Color of the sponge. So, from a technical standpoint the color of the sponge should also only reflect the use of a different dye on the sponge. An orange sponge = orange dye; a blue sponge = blue dye. However, a company like DHS, I believe, actually uses a different sponge and a different quality of sponge, when they use the blue sponge with a Hurricane or Skyline topsheet. I will use Butterfly rubbers as an example again. Sriver, Bryce and Tenergy all have different sponges just like they have different topsheets. Lets say that they decided to have 3 versions of a new Rubber. The Lets call this new Rubber, SBT (Sriver, Bryce, Tenergy). So lets say there is the "Commercial" version of SBT and it has the Tenergy topsheet and the Sriver Sponge; lets also say that they choose to dye this sponge yellow. Then there is the "Provincial" version of SBT and they use the same Tenergy topsheet, but they use the Bryce Sponge; Lets say they choose to dye the sponge on this one Orange. Then there is the top of the line version the "National Team" version of SBT: Lets say it uses the Tenergy Spring Sponge and they choose to dye the Spring Sponge Blue.
So in the scenario above, the different colored dye does not actually change anything. The actual determining factor of whether the sponge is better is the kind of sponge used. But the company has decided to use a different color dye to make the differentiation between the different sponges visible. Does that make sense?
Lets look at Tenergy 05, 64 and 25 for a moment to examine another issue. The Spring Sponge on all three Tenergy rubbers is the same. The topsheet on all three Tenergy rubbers is--brief pause for dramatic effect--THE SAME. I know, many people will not get this or believe this, but it is true. The topsheet itself is exactly the same on all three. So what makes the three so different, and they are different. THE SIZE OF THE PIMPLES. Even though the pimples face in, the size of the pimples is what gives each of these three rubbers different playing characteristics. Tenergy 05 has the smallest pimples which means they have the highest degree of deformation which makes 05 the slowest and spinniest of the three. 64's pimples are about half way between the size of 05 and 25 so 64 has more spin than 25 and less speed; but it has more speed than 05 and less spin. 25, having the largest pimples feels the hardest and fastest. And, because the pimples are soooo large, even though they are facing in, they allow the least deformation of the rubber and give the hardest feeling, the most speed and the least spin. Still they are more than spinny enough and you get more than good enough control from them.
I cannot think of any rubbers where the sponge stays the same hardness while they have versions with softer or harder topsheets, but Tenergy is the closest example to this. With Tenergy, Sriver and Bryce, the black topsheet and the red topsheet play the same. The info on the DHS topsheets not playing the same might come from the fact that so many of the players on the Chinese National Team use Black DHS rubbers for the forehand and their red rubbers are a different brand, often Tenergy, for the backhand.
The Club I used to play at NYTTF (which closed down in November which is why I cannot play there any more) would only sell black DHS rubbers and would not stock the red ones. But, again, I cannot honestly tell if there is a real difference between the red and the black, in part because every single DHS rubber I have used plays slightly differently. So I think it is just as possible that the issue has to do with quality control in Chinese products.
I have to be honest, I don't really know the answers but those are educated guesses about things like the blue sponge on the DHS Hurricane and Skyline that the players on the Chinese National Team seem to use, and on how different hardness of sponge and topsheets might combine.