I'm sure you do- and I know how frustrating that can be. Unfortunately, the outcomes of children on the edge of care are not measured in the same way or in the same depth.
Interestingly, a recent report from the Rees centre suggested that the impact of children's pre-care experiences outweighs the impact of being in care on educational outcomes:
The studies reviewed suggest that the relationship between being in care and low educational outcomes is partly explained by pre-care experiences, such as maltreatment and neglect. The difficulties faced by these young people may pre-date entry into care but even if reduced, in some studies these persisted once in care.
It also suggests that being in care does not exacerbate or reduce these difficulties- so, in one sense, this supports what you are saying. It certainly tackles the accepted idea that it is the care system which damages the educational outcomes of children, although it recognises the issues which come with being in care, such as placement/school moves.
I would advocate (and anticipate) the broadening of the virtual head's remit to include children in need and adopted children- but I see the identification of LAC as a separate and distinct group as a step forwards on this path, not backwards. For the first time, discussions are being had in school about the impact of trauma and neglect on children's behaviour, relationships and learning, and that is a very good thing.