Hello @v.chow - I googled a lot about this and see that 12 month eligibility is only for functional English. My wife has a positive assessment along with competent score in PTE, so I am assuming its not applicable in my case. All her education has been in English medium and was submitted for a positive ACS assessment, so I would like to believe her score will be applicable for 2 years.
The 12 month criteria for PTE is only applicable if the secondary applicant’s education is not in English medium and has no other way to prove English abilities apart from taking a PTE test.
@Anil.Gupta - Your views if my understanding is correct or I am just being optimistic
Extract from one of the googled links.
### Functional English
If your spouse or partner has less than functional English, then you would need to pay the “English Education Charge” to cover English language tuition in applying for skilled migration.
You can show you have functional English ability by providing evidence of one of the following:
1. Completion of a degree, higher degree, diploma or trade certificate that required at least 2 years of study in English medium
2. Completion of all years of primary education and at least 3 years of secondary education in English medium; or
3. Completion of at least 5 years of secondary education in English medium; or
4. Scoring at least 4.5 averaged over the four components of the IELTS test within the 12 months before application, or during processing; or
5. Completion in Australia of at least 1 year of full-time study or equivalent part-time study towards a degree, higher degree, diploma, or associate diploma in English medium.
6. In some circumstances, functional English can be established via interview