If your certificate says 'Master of Science' then it means you have a masters. Send it to IQAS, you will definitely get masters evaluation.
IQAS evaluates credentials based on credits and not based on duration or % of marks scored.
My PG certificate by WES was evaluated as PG Diploma(One Semester). However, the same PG Certificate was evaluated by IQAS as Graduate Certificate(1 year).
The reason from WES is that I completed my PG Certificate in 6 months whereas it was a 1 year program but IQAS evaluated it correctly because it still took me the same number of credits to complete the program in less than a year. IQAS evaluation was spot on