I'm very sensitive to that. For me, one click on the adjustment is the difference between comfort and total numbness. This is how I have mine set up...Maybe your saddle is slightly tilted back so the nose of the saddle is pushing onto your nuts
Have you got larger than average nuts ?
I once read an article by a cyclist who had worked as an A & E doctor and he said that he'd had several cyclists in over the years with exploded testicles from traumatic 'nad-to-top-tube impacts!