Electroless nickel plating on brass per ASM 2404, class 2

I have brass parts that require electroless nickel plating for corrosion resistant. AMS2404 [link is to spec at TechStreet], class 2 requires post plating heat treatment for harden the deposit. Do I actually get better adhesion of nickel by specifying class 2? What are the advantages and disavantages between class 1 and class 2 EN on brass?

Hardening electroless nickel coatings will severely reduce their corrosion resistance and may cause the coating to crack. However, it will improve adhesion.