I take issue with that statement as you can’t have the fuel bladders and the passenger seating pallet modules in at the same time.
The image from Airbus’s website shows what needs to get swapped.
View attachment 77643
As I understand it, the various modules get unlocked and slide down to the side cargo door then can be unloaded.
Depending on the degree of ground support systems it should be swappable from 45min to several hours.
I don’t think it’s something you really want to swap out all the time, simply because it increases the risk of somebody breaking something, or not affixing something correctly.