It's also a matter of the number of people and nights. We're just two people, staying for three nights (because Cabana Bay is cheaper than WDW for moderate), so it's cheaper to buy the Express Pass. But add a couple of kids and that would change.I always do a split stay between Disney and US/IOA staying onsite at each. Royal Pacific is the least expensive of the US Deluxe resorts for the onsite perks. You can purchase an Express Pass for each party but pricing is based on the busyness of the parks and June might be pricey. Do your math for two day Park to Park Universal passes plus Express passes for your dates and a one night stay at Royal Pacific with two days of Express. You can use the free Express Pass for your arrival date and departure date and you can experience a very nice hotel for a night.
I haven't figured out why people doing split stays like to make it just one night at US unless they're staying at a value resort at WDW. The pricing otherwise doesn't justify it, and seven days WDW immersion isn't worth that much more than five days.