I think the site sponsor would probably rather you list high so they can keep prices high and collect larger commissions. They don't care who pays the commission, but they do benefit if the contract sells for a higher price. And, if it takes a little longer to sell the contract, I think they'll take the larger commission over the instant sale.
I made a couple of low offers to listings on the site sponsor back in early June. Had some very nice conversations with one of their brokers. Their brokers are super nice people. But, I remember the broker gently suggesting in response to my low offers, well, I think this contract will eventually settle right about at $X/point. It was a little lower than the list price, but it was pretty clear to me that she was trying to set the expectation that the contract was worth that, and if I wanted it, that's what I needed to be prepared to pay. Can't say I blame them. They're in a business. And, they make money through volume and higher than average prices.