From Fallen London Wiki
I wish I had thought to record the values I saw, but the gained tribute now scales with your Offering Riches. I think it started to decrease somewhere around 250? And stabilized at 22 before I hit 500 Offering. The Offering Gain stayed the same, I'm almost sure. I got a ton of Mountain-sherds from the Sixth Coil and then they go and reduce their tribute value with this right after >.<