In Depreciation book, do i need to define my official value model again?

Dear 

Can someone briefly explain to me the difference between the Value Model and the depreciation book?

I do understand that you can have several depreciation book where one could be the official government rate or method and the other could be for corporate reporting purpose only;

BUT if I do Setup my Value model (to be the official depreciation that affects my ledger) and i go to my depreciation book (to define my other internal books) , Should I AGAIN define a depreciation book for the same value model that i defined earlier in the Fixed Asset Group >> Value Model Tab?

just in case i didn't explain myself well, should i do the below 

Value Model

1. Straight Line (Official Depreciation)

Depreciation Book

1. Straight Line (Should I define my official depreciation once again here in the depreciation book?)
2. Double declining rate 10%
3. Double declining rate 20%

your feedback is mostly appreciated

Regards