Ok I can see the issue with this. The idea in mind is "suppose" to encourage people to set their HP's for an inn in other places other then Ulda, however that won't happen. The Ulda Inn will be use as the main Homepoint used to travel back to town when needed while the secondary HP will be used when doing things like Ifrit so they can travel back and forth quicker without having to use anima or at the least only need to use anima once.

There are different ways to go about it. The one mentioned was the return timer would be the same 15 min shared timer but what if the inn timer was longer. The Inn return timer should be 12hrs, since the main idea for the Inn return is so you can log out for the night and gain rested xp. There's no need to have the Inn be set for 15 mins, unless you for some reason need to go back and pull things out of storage every 15 mins.