Despite inscription "improved lifetime" shorter lifespan

I use the Dulux S in my toilet. The original copy is kept at least 6 years (also it had the previous inhabitants already in use, probably so they still held much longer). The replacement copy in mid-2010 bought now held only 2.5 years. I'm curious how long it will keep selling now, third copy. From an "improved lifetime" (also already stood on the copy of 2010), I could at least last time not notice the contrary.