I had a really persistent smell with mine and the advice I had was to try hot and then cold, then bomb it.... and also to run it on "ECON" without the aircon for some of the cycle as I was getting a surge of the "wet tramp" smell when I switched the aircon on and off.
I eventually got rid of it for 12 months + by running the car with heating on "HI" for 30mins+, then "LO" for around 15-20mins (i.e. until it's properly cold), THEN put the Wynns in there.... and once the spray is finished, pop the econ button in for the tail end of it all.