Hi guys,
I am in the same situation, I have obtained 900 hours of work experience in NOC Level A, and I am about to change to another job under NOC level B, hopefully, I can get 1560 hours experience after this job.
I have read all the answers in this forum and it seems the 1560 hours come from different jobs under NOC level O, A, B does count in terms of hours requirement but, it doesn't guarantee you get the award points (40 points) when you actually in the applying process( which I think the points you have in total without the 40 points will be too low to be invited).
I hope someone who actually has been through all of this could help a little clarifying this type of issues