6PE over MPLS (LDPv4), next-hop question

Hi,

In 6PE over MPLS, the next-hop of the IPv6 prefix will be changed to IPv4 of the loopback IP of PE, when exchanging routes via MP-iBGP with remote PE.

Then may I know anyone know by what rationale that 6PE doesn't need to set "next-hop-self" under "address-family ipv6 labeled-unicast" for iBGP with remote PE?

Is that simply becoz it is MP-BGP with AFI/SAFI 2/4?

Thanks

Recap the IOS XR config in the workbook:

router bgp 100
    address-family ipv4 unicast
    address-family ipv6 unicast
        allocate-label all           
    nei 2.2.2.2
        remote-as 100               
        update-source loopback0
        address-family ipv4 unicast       
            next-hop-self
        address-family ipv6 labeled-unicast