GS006

Attribute: UPSTREAM

code		description
A		A tag is upstream most tag
B		B tag is upstream most tag
C		C tag is upstream most tag
D		D tag is upstream most tag
MA		A tag would be upstream-most, but tag is missing
MB		B tag would be upstream-most, but tag is missing
MC		C tag would be upstream-most, but tag is missing
MD		D tag would be upstream-most, but tag is missing
X		Upstream determination not possible due to orientation of log or missing tags