The speakers/propaganda

I noticed that when I use speakers near the prayer statue at the center, with the bonus of the little burn pit things I get almost 4x speed, is that supposed to happen, or am I overthinking it.

With both bonuses, I get the max 175 in like 30-45 seconds with all the slots filled and no followers bonuses (for the prayer or working traits)

I was curious to see if anyone else thought of this strategy or have disproven it?