Is there any reason to have 2 Avalanche X-Factor players activated?

I bought Patrick Willis last night and already have Prez who still plays well for me. I'm going to user Willis as my sub/Lb and I run a 49ers/Legends theme team so his ×2 49ers team chem is helpful. I heard that avalanche only works if the player is user controlled? So any reason to use both Willis and Prez and their x-factors? I like the avalanche x-factors in that it helps with fumbles and is always a threat against the offense and especially a run heavy offense but is it best to just use Willis' x-factor and sell Prez? Can I not put my tackling on aggressive to where the CPU will hit stick my opponents and cause fumbles with a CPU controlled avalanche player?

Unstoppable Force > Avalanche

If you still want an Avalanche X-Factor than keep WIllis and sell Prez like you said.