SPP highlight recovery question...
Well, Nanda... my reply will certainly not bamboozle you with technicality!
Firstly, it seems that you are adept enough with the various programs you have used, so nothing specific.
I just do it "by eye" for highlights: when "sufficient" detail appears I stop. Certainly, in SPP it sometimes means making other adjustments, like Fill Light; and in Photoshop - where I mainly use Shadow/Highlight - I have to re-tweak the shadows and Midtone Contrast. (And sometimes I use the Exposure/Gamma/Offset adjustment.)
But in the first instance, I see "what's available" in highlights in SPP by sliding the Exposure all the way "down".
Hope that's clear