Every piano, even the most expensive concert grands, has problem notes. Some may twang a little, others may ping. If the strings have been properly rendered, leveled and mated to the hammers during prep then those twanging or pinging notes will have to be dealt with another way. I have discovered a good and accurate tuning can either sharply reduce or even eliminate twangs and pings.
A good tuning is also essential prior to deciding whether or not any hammers need voicing. During my tuning sessions with the Omega, I have found that individual notes that either sounded dull or too bright have been put right by very careful accurate tuning. This of course implies that the piano was properly voiced by the factory prior to shipment.