rate of payment vs installment rate

rate of payment and installment rate both are nouns.

Word	Noun	Adjective	Verb	Adverb
rate of payment	Yes	No	No	No
installment rate	Yes	No	No	No

As nouns, rate of payment and installment rate are synonyms defined as:

rate of payment and installment rate: the amount of money paid out per unit time

Other synonyms of rate of payment include payment rate, repayment rate.

rate of payment (noun)	installment rate (noun)
the amount of money paid out per unit time	the amount of money paid out per unit time