回复：理论上确实如此，但事实上有不少人在只有1份140PD当前的情况下也成功了

I think you misunderstand what Pjiang said. You can only transfer the I-485 from the I-140 with non-current PD to the I-140 with current PD, not reverse. In your case, your Eb2 I-485 (if any) can be transfer to your EB1 I-140 because the EB1 I-140 PD is current, not reverse by this point because your EB2 PD is not current.