Expiry or expiration?

Do these 2 sentences have particular reasons? Could we use both?

A. Not less than 30 days of the expiration.

B. Not less than 30 days of the expiry date.

Solution 1:

Expiry and expiration are synonyms that can be used interchangeably: (from TFD)

• a coming to an end of a contract period; "the expiry of his driver's license", the expiration of a contract; termination.

Ngram - BrE: expiry date vs expiration date

NGram - AmE: expiry date vs expiration date

Ngram shows that 'expiration' is the term more used in AmE while in BrE both terms are used, though 'expiry' appears to be more prevalent.

• (UK) Check the expiry date on your passport.

• ( US) Check the expiration date on your passport.

• not less than 30 days before expiry/expiration (date).

Solution 2:

A. Not less than 30 days of the expiration.

B. Not less than 30 days of the expiry date.

Those two fragments are ungrammatical. When using "of the expiration" we cannot use "not less than".

*Not less than 30 days of the expiration [UNGRAMMATICAL]

At least 30 days from expiration|expiry OK

No more than 30 days from expiration|expiry OK

Within 30 days of expiration|expiry OK