This was the practice of Rasoolullah (sa). He was consistent in praying the last Ashrah of Ramadan. It did not matter whether it was an odd night or even. The point is that one should not worship the bare minimum like dipping your toes in a pond; rather, the idea is to deep dive and indulge in worship fully. If it’s a Sunnah, it should be sufficient for us to embrace it heartily.