Care about standard usage? Then learn the finesse of the English language.
I think you have *the* upper hand (not, an upper hand). The idiom is used with the article “the”, not “an”.
Don’t *jump to conclusions* (not, _jump into conclusion_).
I got the job through the *good offices* of my uncle (not, _good office_). The influence and power with which a person can help is his or her good offices.
GAB