n5 The parties do not challenge the finding of the trial court that both Steiner and Mobil are "merchants" within the meaning of section 2104, subdivision (1), and thus within the meaning of section 2207, subdivision (2), as well. Moreover, the parties do not argue that the applicability of section 2207, subdivision (2), subsections (a), (b), and (c) turns upon whether the terms of Mobil's acceptance were additional to, or instead different from, Steiner's offer. Despite the parties' agreement in this case, however, the question of the relevance of the distinction between "additional" and "different" terms has become a matter of some controversy among courts and commentators.

    Section 2207, subdivision (1), refers to acceptances in which terms are either "additional to or different from" the terms of an offer. Section 2207, subdivision (2), however, expressly concerns itself with only "additional terms." Noting this difference, several courts and commentators have concluded that section 2207, subdivision (2), applies if an acceptance adds terms to an offer, but does not apply if an acceptance alters the terms of an offer.  Other courts and commentators, however, suggest that section 2207, subdivision (2), applies without regard to whether the varying terms of an acceptance differ from or add to an offer.

    We conclude that the applicability of section 2207, subdivision (2), should not turn upon a characterization of the varying terms of an acceptance as "additional" or "different." First, Uniform Commercial Code comment 3 specifically states that "[whether] or not additional or different terms will become part of the agreement depends upon the provisions of subsection (2)." (Italics added; see also UCC com. 2.) Second, the distinction between "additional" and "different" terms is ambiguous. Since an offer's silence with respect to a particular issue may indicate an intent to adopt the code's gap-filling provisions, even an acceptance term which at first glance appears to be plainly "additional" is at least arguably "different." (See Air Products & Chem., Inc. v. Fairbanks Morse, Inc. (1973) 58 Wis.2d 193 [206 N.W.2d 414, 424].) Third, the distinction between additional and different terms serves no clear purpose. If additional and different terms are treated alike for purposes of section 2207, subdivision (2), an offeror does not, as some contend, lose "the ability to retain control over the terms of his offer." (Duesenberg & King, supra, at p. 3-37.) Under section 2207, subdivision (2), if the offeror wishes to retain such control, he may do so by framing his offer so that it "expressly limits acceptance to the terms of the offer . . . ." (§ 2207, subd. (2)(a).)