Part 61.129 in the FARs discusses Commercial Pilot aeronautical experience requirements. In section (a)(3) of that part you have "20 hours of training on the areas of operation listed in 61.127(b)(1) of this part that includes…(10+ hours instrument, 10+ hours complex, etc etc)

My question is whether the 61.127(b)(1) "Areas of Operation" can be carried over from previous certificates and ratings, i.e. Private and Instrument…or do they need to be entirely separate logged hours?