Question about Mears shuttle

[jimandami]

DH and I are staying at WDW for 7 days in a couple weeks. We have also booked one night at Uni in the middle of our stay. Our plan is to go over on Tuesday afternoon, check-in to hotel, and hang out. We will go to the Uni parks on Wednesday and then head back to WDW that night. So, our question is this: has anyone booked the RT transportation with Mears shuttle and then used the two legs on separate days? I called Mears and she told me you couldn't do that, but we all know how unreliable some phone operators (um....Disney CMs....I'm talking to you!) can be. So, I was just wondering if anyone had done this successfully? If not, we will just use Uber or Lyft.