What determines how many points a game will costs when create a gift?

+1 awesome avatar

Was one of them on sale? It's the retail (MSRP) price and not the actual price at the time. (Not to mention that it tracks the US Steam store.)

Kesseki means packages, not bundles [though SG does also have packages which are termed bundles, hence the likely source of that confusion]. In other words, Kesseki means game collections which contain multiple games, such as this one.

Due to how the Steam API (mal)functions, if a package goes on sale cheaper than the base game, and the package and the base game are both listed on the same store page, the package price will become the featured price for that page. The Steam API makes it so that checks against the base game on a page actually reference the featured price, instead of the price of the base game itself. Thus, when the featured price- which is normally the base game- is replaced by an on-sale package, the base game misreports its price all throughought the Steam Store. As SG determines P and CV values off of the same element, those are affected in the same manner.
tl;dr Valve did a sloppy job with its API, and sometimes base games will instead claim to have the retail price of packages which include those base games, rather than their own retail price.

As an example, the package I linked has a retail value of $50, while Deponia, a game within it, has a value of $20. If the package goes on sale down to $15, while Deponia remains at its normal price of $20, Deponia will claim to be on sale at $15 out of $50. From a purchaser viewpoint, knowing that Deponia is down to $15 is useful- it's still a discount off the base game. Thus, likely the reason Valve arranged the setup as it is. The issue is that it reports the package's normal retail price as well, rather than its own- thus claiming that the game is discounted from a base retail price of $50.