That's interesting. I've never used Cobalt Flats, based on my impression (from reading TB) that they have a pretty flexible feel. I instead prefer strings that feel pretty stiff, such as Chromes, LaBella DTFs, DR nickel Lo Riders, Elixir Nanowebs, etc. And, like you, I can't stand the flexible feel of the TI Jazz flats.
I've used Pressurewounds before, including twice on my ceramic SR 5, and liked the way they sounded on that bass. However, they're about as flexible a string as I'd use and I'd actually prefer an even stiffer feel (FWIW, I love nickel Lo Riders). Since you've gone through some recent string changes, do you have an impression of how the stiffness or flexibility of the Cobalt Flats compares to that of the Pressurewounds? Mauybe my impression is wrong?