nip and tuck

"Slam Dunks and No-Brainers" からの一節です。
"..., he altered the brand's image with a few language nips and tucks."
nipもtuckも知らない単語ではありませんが、この言い方はイデオムの匂いがします。
そこで辞書です。
COED
adverb & adjective: closely contested; neck and neck.
noun informal: a cosmetic surgical operation.
nipとtuckを顔に施すことからこの名詞意味ができたのは容易に想像できますが、名詞/形容詞の方の意味は語呂がneck and neckと似ていないことは無いのですが何故この様なイデオムの意味が生まれたのか不思議です。他の辞書も見てみました。
Dictionary.com:
A) Based on the Random House Unabridged Dictionary, c Random House, Inc. 2006:
with each competitor equaling or closely contesting the speed, scoring, or efforts of the other: It was nip and tuck as to which sailboat would reach port first.
B) Based on the The American HeritageR Dictionary, adv. & adj.:
So close that the advantage or lead shifts from one to another and is virtually indeterminable.
C) Based on the WordNetR 3.0, c 2006 by Princeton University:
adjective
1. inconclusive as to outcome; close or just even in a race or comparison or competition; "as they approached the finish line they were neck and neck"; "the election was a nip and tuck affair" [syn: neck and neck]
adverb
1. even or close in a race or competition or comparison; "the horses ran neck and neck"; "he won nip and tuck" [syn: neck and neck]
noun
1. plastic surgery to remove wrinkles and other signs of aging from your face; an incision is made near the hair line and skin is pulled back and excess tissue is excised; "some actresses have more than one face lift" [syn: face lift]
語源に触れている辞書は見つかりませんでしたが The Free Dictionary には次ぎ意味も掲載してありました。
small changes or reductions made in order to improve something. A nip and a tuck in their household budget would give them the extra money they need.
冒頭に引用した文での "nips and tucks" の意味はこれが一番近いですね。　それに"nip and tuck" あるいは "nips and tucks" が追いつ抜かれつの勝負を意味する場合でもその差は僅かなものなので意味としては共通なものがあるなと勝手に納得することにします。