In case you haven't seen this on Interval's website...
Exchange Fee Update
Effective February 15, 2017, the new Internal Exchange fee for properly submitted exchange requests has been reduced to $139 for Vistana Signature Experiences owners.
That's all the information available. I'm not sure what the "properly submitted exchange request" part is all about? Playing around with online trades, we get the discounted $139 fee (instead of $189) for trades into other Vistana properties only.Effective February 15, 2017, the new Internal Exchange fee for properly submitted exchange requests has been reduced to $139 for Vistana Signature Experiences owners.