KERML_ — Ambiguity In Directionality InOut semantics

Literal Values
inout
"Values of the Feature on each instance are determined either as in or out directions, or both."
In and out discuss 2 concepts of 'determination' of an instances value, and 'use' of an instances value
Is 'inout' ambiguous as to the features determination and use completely or still constrained?
Both 'in' and 'out' require opposite 'determination' than 'use', but can inout allow same 'determination' and 'use'?
To be more clear, can an inout feature be 'determined' 'externally' and 'used' 'externally'?
How is 'inout' different from not providing a directionality constraint?
How does directionality work with specializations like subsetting/redefinition, should there be constraints?