When does your stay actually start? If you aren't at the 60 day mark yet it will only show the 30 days.
You can use this calculator to figure out your important dates, if it should be showing 60 days by now you might need to call tech support? http://www.themouseforless.com/walt-disney-world/planning/date-calculator/
I was just going to buy tickets for my Jan 2018 stay but glad I saw this. You can only book fast passes 60 days in advance? I always thought it was 90 days in advance? I usually book a package and this was going to be the first time I booked tickets separately.