extraneous duty allowance vs extra duty allowance

extraneous duty allowance and extra duty allowance both are nouns.

Word	Noun	Adjective	Verb	Adverb
extraneous duty allowance	Yes	No	No	No
extra duty allowance	Yes	No	No	No

As nouns, extraneous duty allowance and extra duty allowance are synonyms defined as:

extraneous duty allowance and extra duty allowance: an allowance payable to employees who are given special assignments or perform additional duties.

Other synonyms of extraneous duty allowance include special duty allowance.

extraneous duty allowance (noun)	extra duty allowance (noun)
an allowance payable to employees who are given special assignments or perform additional duties.	an allowance payable to employees who are given special assignments or perform additional duties.