Haven’t read all the replies but your park level 100% plays a roll in your TH trades.
Managing 3 accounts for a while there were 2 lvl 99 accounts and one account I recently brought up from in the 40’s. The lower lvl account would never get high decoration to coin trades. Maybe 1,600,000 for an AF at most. The lvl 99 accounts routinely see trades for up to 2,200,000. As that account lvl increase i noticed the amount of coins we would get for decorations would go up as well.
It was very apparent with the deco to coin trades, can’t say other instances really jumped out at me and i could not say for certain without having collected data.