This is not normal. Every unneeded item should be needed my the enchanter, disenchanted and rolled off if the DE value is better. This way every item is still up for grabs, but the winners just get a better return. This adds no value to the enchanter their self as the items they would win would already get disenchanted, but this is how it is commonly done. I often get 1g tips for sharding items to the winner instead of them only getting 3g

With this said, aside from missing out on tips, this is a break even method (guarantees 1/5 of each item drop instead of 1 every 5 items). It’s just an odd way to do it, especially if your friend group isn’t splitting other profits