cfl color temperatures and full spectrum bulbs

Okay, I'm gonna be starting a grow soon and I have a question. So I'm looking into this bulb that says it's 'full spectrum'. I know that people say that you need a 6500k-5500k light during veg stage and a 2700k-3000k bulb during flowering. I'm not quite sure what this accomplishes and so I'm wondering whether or not I can use this 'full spectrum' bulb throughout the whole cycle. If so, why does the bulb say that it's a 5500k? Thanks in advance.

6500k bulbs are used to vegging your plant, and 2700k are used for flowering.

Yes and what about these full spectrum bulbs? And can I use a 42w 6500k with a 13w 2700k bulb throughout the whole cycle?

https://www.rollitup.org/cfl-fluorescent-lighting/107992-tutorial-growing-cfls.html

Read that^ It should explain most things about cfls and what to use.