Transaction value acceptance governs export valuation; declared values may be queried but exports released pending verification. Transaction value is the primary basis for valuation of export goods and shall be accepted even where buyer and seller are related unless the relationship influenced the price; if transaction value is rejected after a reasoned query, valuation must proceed sequentially through the alternate methods, with goods ordinarily released against an undertaking while representative samples are retained and investigations are conducted, except in cases of serious violations where detention or seizure is permitted.