I'm a local, and I didn't know about these changes until now:P...I would say..the more the merrier...so to avoid any mishandling I would use redundancy.
My mail address goes like this (I buy banknotes from Ebay, so I receive international mails every 2 weeks)
Av Pardo ###
Miraflores, Lima 18
I guess with the new changes, I would use
Miraflores, Lima 18 / 15074
Mail is sorted by people after all (I highly doubt we use lasers or optical scanners here), so I'm pretty sure the "Lima 18" is already branded in their heads for years to come.