Aw, I'm glad you liked it, and that I was able to surprise you. :)
That's the way I changed the original ending. In the original ending, only three of the children came to the present (Hannah, Clara, and David), while Joshua, Thomas, and Patience weren't able to go through the portal. Sarah was left at the end of the book still trying to figure out a way to reunite everyone.
I changed it to bringing all of them to her to tie up her portion of the story (for the most part....she still has a time travel-related project she's working on at the end), which is satisfying to readers, since they don't have to wait for a new book to find out what happens next. At the same time, the new ending left plenty open for new stories with other characters like Matt, Jacob, and Lizzie, as I mentioned before. I like it better this way. :)