I'm pretty sure it has changed, because I clarified with
UT just a few weeks ago what their refund policy is. For regular park tickets, it is a 365-day return policy. But for special event tickets such as Disney After Hours (I had asked them specifically about After Hours at Epcot and H2O Glow at Typhoon Lagoon) it is 90 days. Meaning you have to have purchased the tickets within 90 days of the date you are requesting the refund, even if the event date is still in the future. So, hold off on buying special event tickets from them until your event date is 90 days away (or less), if you want to be able to decide as late as the day before whether you are going to attend or not.
But, if you look on their site right now, it says that the MNSSHP tickets are non-refundable.
And then further down the page, it's got a confusing mish-mash of 365-day and 90-day return policy. I pointed out to them that their site has really poor wording, because for the After Hour tickets it had that same mash-up of saying "365-day refund policy" and then later in the paragraph saying "90 days", which is why I emailed them for clarification.
So I would double check with them before purchasing MNSSHP tickets to see whether they are refundable at all, given how much contradictory stuff is in their fine print.