Those creases are a PITA as are the perforated seats (but nice when they are cooling your nether regions on a long road trip or Florida hot day). Sometimes the crease is just a wear spot in the leather and not necessarily dirt. It may not come out if it is already worn out from use.
When nothing else (product of your choice or elbow grease with cotton rag or microfiber is working), then you might have to resort to less
traditional methods to get back to square one.
I will usually pull out the Magic Eraser if I am meeting with resistance. I know some guys will say no way, the chemicals and abrasive nature of the sponge on the leather, but it does work. I have used it on the 06 and the 13 leather seats with great results and plenty of clean interior compliments.
Pick a test spot, make sure the Eraser is wet, but not dripping wet and gently work that area and wipe clean. A brand new Eraser will yield very quick results. You can still use your leather cleaner along with the Eraser for lubrication and cleaning purposes. You want to go slow and easy so that you don't strip the sheen off. If you go hard core, you will clean the seat and it will be a matte finish upon completion.
If you like how this is working, then go a bit further wiping as you go to compare and see if you missed anything. I wipe the leather down once again with a cleaner and microfiber before moisturizing it with your favorite leather treatment. This is a key step at the conclusion to condition the leather since you are mildly stripping the natural oils out.
Some guys on TYF and many other forums recommend Magic Bubbles as well. I have not personally used this recipe, but it is another option to help clean really ground in dirt, again going lightly, cleaning and moisturizing.
Go slow, do a test spot, clean again and moisturize. That should do the trick. Hope that helps a bit.
@MichaelSE