Nikkan Sports is reporting that there might be two posting system proposals on the table right now.
This information is coming from Yomiuri Giants’ owner Shoichi Oikawa. He spoke to reporters after an owners meeting in Tokyo earlier today. There may also be an additional level for players under twenty-five, since the CBA limits the size of their contracts.
Source: Nikkan Sports 9/13/2017
[UPDATE 9/14 @ 9:30am]
According to Sponichi, if the percentage system sticks, NPB teams might also be given refusal rights. Since posting fees will depend on the value of the contract, NPB teams will not know how much they will get until after an agreement is made. If they feel the amount is too low, refusal rights will give them a chance to refuse the terms.
Source: Sponichi 9/14/2017