Address field names differ in iTunes Account and AppleID Account

I wonder if a difference in how address fields are named in my iTunes Account and my AppleID Account might explain why, when I try to change credit information, the CC Security Code does not save.  (In a 2011 Apple Discussion called “iTunes not saving my CC security Code”, a responder said that card billing information has to match your iTunes account exactly.)

I have been trying (unsuccessfully) to update credit card in iTunes and AppleID Accounts from my iMac.  Credit card information, including expiry date and cc security code, are on the same screen with address field information.  I notice that the field names for New Zealand addresses are different in iTunes Account and AppleID Account (appleid.apple.com).

In my iTunes Account, the field names for the Billing Address are close to New Zealand usage:

First Name

Last Name

Address Line 1

Address Line 2

Suburb

Postcode

City/Suburb

Phone Area code

Phone

• Information input into the “Suburb” field disappears after clicking the “Done” button.

• It is odd that the “City/Suburb” field isn’t just called “City”.  

• The Country/Region field, which is edited separately from the Billing Address information, correctly says “New Zealand”.

In AppleID Account the field names are different:

first name

last name

street address

apt., suite, bldg

town

postcode

city

country/region

phone area code

phone number

• “town” is a required field.

• I put my suburb into the “town” field and it is retained after saving.

• The most glaring oddity among the field names is having separate “town” and “city” fields.

So, is this difference in address field names important? Might it be relevant to my problem with saving cc security code?