I'm making a little game in my world, and I'm making Armor sets, and I made a Light Armor Set, and I expected for the Speed to stack up to 40%, but instead it only stayed at 10%.

Here is the Command:
/give @p 298 1 0 {display:

{Name:"Light Leather Cap"}

,ench:[

{id:34,lvl:100}

],AttributeModifiers:[

{AttributeName:"generic.movementSpeed",Name:"name",UUIDLeast: -10000, UUIDMost: 10000, Operation: 1, Amount: 0.10}

]}

Did this for all pieces of Leather armor and I equiped them and the Speed attributes wouldn't stack, It's the same for Health attributes!