But there is a difference in pitch between the two props so the platinum props may produce more lift having slightly more pitch. The increased pitch plus improved tips is what helps reduce the decibels.I expect the more flexible platinum props to have a slightly lower efficiency.
They are purely meant to lower the noise, not to increase lift perse.
I might be wrong of course, I don't use platinum props because I see no benefit. The Pro is already the quietest drone on the market after the Platinum.