I found out if you go into creative mode befor placing down your treasure it will let you continuesly place treasure down. I only had one Guilded Harp, One Guilded Urn and one Bountiful Treasure Chest.
It let me keep placing more as shown in this image and each one counted to my amout in the coffer as you can see in the other image. Not only that I could fly with the treasure in my hands and teleport with it as well. The Harp and Urn were found in chests so I didn’t have to carry them like I had to with the Bountiful Treasure Chest and went into my inventory.
Not only that the harp, Urn and Chest always stayed in my hands and inventory as I placed them down so it was duplicating the original ones.
You can also duplicate the other ones that you duplicated as well and keep doing it indefinitely. There is no end to how many times you can do it unless you run out of room.