It is the main duties and responsibilities that decide your NOC code, not the title. Make sure the first few duties listed in the NOC code are most consistent with what you do since those ones are considered by CIC to be the "main duties". So if 2173 closely describes your job, then that is the code you would use. Hope this helps.
A word of caution: Your employer should not copy the main duties/responsibilities listed in the NOC code word for word when they prepare your reference letter. They should give you a detailed list of what your actually do.