If you're doing a ghost run at Excalibur, is it better to book through MGM or Hyatt?

From what I've read, if you book through MGM and have Gold or higher the resort fees are very likely to be waived; but you could have trouble getting the nights to post from Mlife -> Hyatt

If you book through Hyatt, you will get the nights no problem but won't get the resort fees waived (?)

So if you are below MGM Gold then you should book through Hyatt because you have to pay resort fees anyway, whereas if you are MGM Gold or higher then you should book through MGM for resort fees.

Is this correct?