What I believe is that your job 'Title' is not the important thing to be matched with your NOC.
What more important is your job 'Duties' for which you are claiming your work experience. If your job duties match with another NOC, you hsould be good to go for that.
I'm not an expert to this, but this is what I understand.
Please check this link.
http://www.cic.gc.ca/english/helpcentre/questions-answers-by-topic.asp?top=29
It says, "If after submitting your Express Entry profile you are invited to apply, you must show that you did the job as described in the occupational description of the NOC, meaning that you did
all the essential duties and
most of the main duties listed. If you do not show that your experience meets the description in NOC, your application will be refused."
So, what I understand from this is that the NOC doesn't have much to do with the 'Number' of duties for that NOC, but the 'Nature' of the duties, i.e. Essential or main duties.
You must have performed ALL the 'Essential' duties for that NOC.
You should select the noc, of which you can fulfil its essential duties.
It's my inference only.