I tried under both previous PR application and under visitor's visa. In both cases, the answer was you must give new biometrics. (The text I quoted was from the visitor's visa version).If you apply for permanent residence, than yes, you have to provide your biometrics. However, if you have given your biometrics for visitors visa, you don't have to. Tricky I guess?
So the answer seems unambiguous - you must give biometrics, period.
And in this respect at least, the government resources are giving clear, simple, and correct answers.