Budd just keep one thing in mind put the roles and responsibilities mentioned in NOC first among your all responsibilities and keep the key words same as its bit easy for VO to understand your roles just enhance the roles mentioned in NOC by keeping the key words same and try to keep the main statement in the NOC same keep in mind this is the most imp document which decide your entry in Canada . My suggestion is keep the lead statement same and modify the roles and responsibilities as per your exp by keeping the key words same .
Note from my Lawyer :
Classifying work experience for the purpose of a permanent residency application is not an exact science. We can provide you with advice based on our significant experience in these matters, however the final determination as to whether the documentation you will provide is sufficient evidence of the fact that you have worked under an eligible NOC will be in the hands of the visa officer who analyses your file. Visa officers have significant discretion in this respect.
The official guidelines state that you must provide evidence that you performed “a substantial number of the main duties, including all of the essential duties” for a given NOC as well as performed the actions described in the lead statement (the first paragraph) of the relevant NOC description (in addition to evidence of your start and end dates, job title, salary, etc.)
Hope it will help you