"When you migrate to a new generation, your Guardian will follow you, so long as you stick to your platform. Your friends will need to follow you, too. Every box gets a unique version of Destiny, lovingly optimized for the specific platform. " This is from weekly update 8/1/14 mail sack. I have ran across this info in more detail somewhere else with Q&A with someone from bungie, I just can't remember where. Might have been here: http://www.dualshockers.com/2014/07/18/bungie-confirms-that-destinys-guardians-will-be-transferable-across-next-old-gen-systems/

Ok, so if you buy the DLC for PS3, and later upgrade to the PS4/PS5(?) I will not have to buy the DLCs again. Even though what you quoted doesn't specifically answer that, we can only assume.

Did some more digging and found this: http://destinynews.net/dlc-works-cross-gen/ Sounds like items and gear from the dlcs will carry over, but the dlc new areas and story type stuff etc... won't.