According to the below para for getting 22, post-graduate diploma is required. I suggest, get it assessed by WES. If they assess as postgraduate diploma, you can claim 22 points.
http://www.cic.gc.ca/english/information/applications/guides/pdf/ECA_table_EN.pdf
A 3 year or more post-secondary credential in combination with any of the post-secondary educational credentials** listed below. This excludes secondary school credentials.
**Note: Post-secondary educational credentials could also include Post-Bachelor's or Post-Graduate Credentials as follows: Post-Bachelor's Certificate; Post-Bachelor's Diploma; Graduate Certificate; Postgraduate certificate; Postgraduate Diploma; a two-year Postgraduate Diploma, specializing in [name of discipline]; a one-year Postgraduate Certificate in [name of discipline]; and, Study Toward a Master's Degree.