JF
My understanding was that nobody's award would be reduced as a result of the Mobility review process and I can't think why receiving points for Going Out would have a negative impact on your Daily Living award.
I would start by contacting the DWP office dealing with your claim for an explanation, although they may be limited as the team doing this are hidden away somewhere and separate from the day to day PIP staff.
Gordon
Nothing on this board constitutes legal advice - always consult a professional about specific problems