on take off, engines are the noisiest, on landing configuration is.
This being said, this is the issue with the P180. Even with the AFM recommendation for "low noise", it does not meet local constraints.
And on top of it, this increases the landing distance so much that they do not meet public transport factorization.
Most of airports today are restricting night ops to Stage 3 minus 5...and even it does exist on props, there is a list of unfriendly aircrafts...
This is why stage 4 emerged, more stringent, yes, but showing only one number...less interpretation...