Scaling scores to the page - stumped!

I know I must be missing something uber simple, but I can't figure it out. Trolled the forums and the handbook. I am sure this is an idiotically simple thing to do...

The tech stuff: Mac OS X 10.10.1 Musescore NB 7a67e63.

What I am trying to do: get just ONE set of parts on the score per page using Ledger size (11x17) paper in landscape for the score (the parts are Letter size portrait).

I have attached my two examples. The first, I Wanna Be Like You, is EXACTLY how I want the score to be. The second, Mr. Zoot Suit, has been scaled down so that it contains the next line of parts on the first page. In addition to being ridiculously hard to work with, it also means that it is hard to track since you have to go left to right, then go down and back to start again. Yet the second piece, as far as I can tell, is set up exactly the same way: same page layout, page size, measure sizes, etc.

Stumped. Help! And thanks in advance!