You have stated on several occasions, that a child in grandparents custody cannot get any benefits off the grandparents SS.
Yet the SSA clearly states in 2010b:
Notes: "Eligible parent" can be a grandparent if they have permanent guardianship.
Did I miss something in the explanation?
Apparently you did, because I've never said that a child cannot get benefits on a grandparent's record. However, permanent guardianship and/or custody in itself does not qualify a grandchild for benefits on their grandparent's record.
In order for a grandchild to qualify for benefits as a child on their grandparent's Social Security record, they must either a) be adopted by the grandparent, or b) both of the grandchild's natural or adoptive parents must either be deceased or disabled. For more complete information on the requirements for a grandchild to receive child's benefits on a grandparent's record, refer to the following section of Social Security's operations manual: https://secure.ssa.gov/apps10/poms.nsf/lnx/0200306235.