From what I understand, it seems you said on your profile you had 2 years of Canadian work experience. Therefore, they were expecting proof of that, which you didn't provide. You only have one year (18 months more precisely), which indeed is enough for CEC.
Once they revised your profile for one year, your score dropped below the cut-off. Meaning, you wouldn't have been selected in the first place, and your selection was invalidated.
That small mistake/ misunderstanding, and the dropped score, is the reason that brings the refusal.
Should your "revised" score have still been above the cut-off they would have processed your application.
CIC doesn't care about hours. They care about months/weeks. Full-time is at least 30 hours. Whether you work 30, 40 or 50 a week it doesn't give you more. Normal vacation time is of course included.
You can order GCMS notes, but your already have the answer here. Just need to re-create a profile with correct number of years.
Though it seems your score is a bit too low to get ITA.