Not sure where you're getting this from. Let's take for example dual pair LII-ESE:
LII
"primary minus-Ti"
"auxiliary plus-Ne"
ESE
"primary plus-Fe"
"auxiliary minus-Si"
In dual pairs, one partner is a negativist and has a "primary minus-" function and an "auxiliary plus-" function, while the other partner is a positivist and has a "primary plus-" function and an "auxiliary minus-" function.