This is how it works. There are two sets of points in the process the first is called FSW (67 out of 100 cutoff) and the second is called CRS (Cutoff decided multiple times a year out of 1200). As an engineer you will first have to qualify for FSW before you can submit your express entry application.
Your primary NOC is the only one used for the FSW points calculation so its best you use the one that gives you the most points (Most years of experience). FSW work experience points.
| 1 year | 9 |
|---|---|
| 2-3 years | 11 |
| 4-5 years | 13 |
| 6 or more years | 15 |
Once your past the FSW stage and filling up the EE application you can now list all your NOCs as separate line items and you will get points for all those years of experience (3 Years max for points). Keep in mind you will need proof of work letter(s) for all those listed NOCs
In your case you can potentially use the senior manager NOC which if I recall correctly will give you more points.