You're welcome! The thing is that I have obtained PGWP previously and I know the procedure and everything but I did a whole 2 year full-time course. I have no practical experience of that mix-and-match situation in which one completed two different degrees of different durations.
So I don't wanna give you any wrong advice. It's better you should call/email CIC as per the information you gathered through this forum and get the confirmation from them. Logic dictates that if you complete a total of 2 years of education, you can receive a 3 year PGWP.
Good luck!