Section 520 - Base periodA claimant's "base period" is one of the following:
1. For the purpose of subdivision one of section five hundred twenty-seven of this article, the term base period shall mean the first four of the last five completed calendar quarters ending with the week immediately preceding the filing of a valid original claim.2. For the purpose of paragraph (a) of subdivision two of section five hundred twenty-seven of this article, the term base period shall mean the last four completed calendar quarters ending with the week immediately preceding the filing of a valid original claim.