Commercial Helicopter Addon vs. Logging PIC
 

I have a certification question that involves some regulations I was hoping someone could help out with. I'm a current Commercial Single & Multi Airplane pilot that will be soon training for my Rotorcraft-Helicopter Addon. I would like to go directly into a Commercial Rotorcraft-Helicopter. Here is what I need help with. According to Part 61.129 (c) - Aeronautical Experience - I will need 35 hrs. of PIC time and 10 hrs. of solo time (or acting as PIC). Can I train towards Commercial Rotorcraft-Helicopter proficiency and log PIC time each flight? What throws me off is another regualtion - Part 61.51 (e) - Logging PIC Flight Time. I don't see anywhere in that part which indicates I could log PIC if I'm not appropriately rated in the aircraft being flown. Am I missing something? Do I have to complete a Private Rotorcraft-Helicopter before the Commercial? I appreciate any insight someone could give.