how does CV works?

The price sale doesnt affect. To get full value of the game, I think, you need to check if the game is bundle or not.

Bundled games are games that have been on bundles or sales with 95% of discount.

I don't know the numbers exactly. In a few seconds you'll get a proper response, accurante and so.

https://www.steamgifts.com/about/faq

Under "What are levels and how can I increase my level?"

Short version:

How much you paid for the game does not matter. At all.
You need to look at the non-sale, full store price in the US region.

Is the game in that exact version (under same name or package name) on this list? https://www.steamgifts.com/bundle-games
Yes ⇒ You get 15% of the US store full price as CV.
No ⇒ You get 100% of the US store full price as CV.

Note: Sometimes it takes time for the bundle list to catch up. If the game goes on a sale of ~75-80% or gets into a bundle at one of the many game bundle sites, it will be added to the bundle list with the date the sale/bundle happened, affecting all giveaways created on that day and later.

ty guys i know how it works Thanks! :D