Actually in the description of the metamagic rod we can read two sententeces:
"This does not change the spell slot of the altered spell."
and
"A caster may only use one metamagic rod on any given spell, but it is permissible to combine a rod with metamagic feats possessed by the rod’s wielder. In this case, only the feats possessed by the wielder adjust the spell slot of the spell being cast."
important: "only the feats possessed by the wielder adjust the spell slot of the spell being cast."
https://aonprd.com/MagicRods.aspx?Category=Metamagic
That i think i need to read that FAQ and or an errata from Paizo about this.
