Yes, the use of "πρεσβυτερος" is less consistent than "ιερευς" as the different books of the New Testament were written at different stages of the development of Christian priesthood. This is why Douay uses both "priest" and "ancient" to translate it, depending on context.
This dual use of "πρεσβυτερος", both familiar and sacramental has seeped into our times. We familiarly call our priests "father"; "papa" is Italian for "daddy"; in Russian an endearment form of "father", "батюшка" ('batyushka) is used for priests.
I've noticed that...
Matthew 23:9 And do not call anyone on earth 'father,'