in order to ... the parties (shall) use

Dictionary meaning of term 'proceed from' does not make sense in this context, one has to understand that while making agreement on something they consider some factors

or
taken into consideration

I would opt for

Total value of the goods, and other details
shall be taken into account
... when the Parties fix the amount of remuneration.

etc.

reasoning skills, for example, ability to critically reflect on practice and reason from own experience and knowledge.
http://www.childsafety.qld.gov.au/practice-manual/sdm/profes...

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Note added at 13 days (2010-10-17 01:22:28 GMT)
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Intuitives prefer metaphor, analogy, and logic, and tend to reason from first principles and hunches.
http://en.wikibooks.org/wiki/Myers-Briggs_Type_Indicator/Dim...

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Note added at 13 days (2010-10-17 01:23:15 GMT)
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To find out what the precise law is that applies to a particular set of facts, one has to locate precedential decisions on the topic, and reason from those decisions by analogy.
http://en.wikipedia.org/wiki/Common_law_system

Коротко и ясно.

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Note added at 13 days (2010-10-17 01:25:29 GMT)
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b. The power of a DSS is limited by the computer system upon which is running, its design, and the knowledge it possesses at the time of its use. A computer system only knows what has been told; they cannot reason from “first principles”, i.e., they have no understanding of a larger world beyond their expertise.
http://faculty.wiu.edu/LL-Andrew/IM443-F01-Lec1.htm