Well, the lifespan of the DPF depends on the amount of ash entering it, and that cannot be influenced by an additive. Ash, which is a metal oxide, is always produced in the same amount, depending on the content of ash-forming substances in the oil (and diesel) and the consumption of both.
The number of uses and, consequently, the number of regeneration cycles can be influenced if the product is actually effective and there is a need for it.