You will get the same answer here as at romhacking.net.
Sounds like you have a big archive file (pkg being a common enough abbreviation of package) controlling this game (or at the aspects you care about), possibly in addition to whatever pointers the internal text format has.
Said pointers are a fundamental concept in hacking really and you are going to need to figure out what goes for this game. They are used because having to have a game (which theoretically should be the same text every time -- DVD Read Only Memory and all that) calculate everything all the time is annoying and a waste of resources you could be using for just about anything else to make the player's life nicer.
The downside of this is when someone changes a file/section length then everything following it get booted back (or brought forward) by however much you changed it, not great when something is expecting a fixed length and has no idea how to handle it when something goes wrong. Not so bad as a dev as you made the format presumably and have tools to handle it, the would be ROM hacker though does not and has to both figure out things and make something to handle it (assuming manual with a hex editor is not an option, and it is usually a bad one).
The changes not being reflected in the running game (assuming you did not load back from a savestate -- if the game had already loaded the original data by the time you made your savestate then you might get that instead) means what you edited might have looked like the file but was not. This can be many reasons but usually are because the dev left their files all over the place when making the game to ship (developer leftovers we tend to call these, wonderful things to explore as it can give all sorts of insights into the development process), or because some random padding was needed and that so happened to be the data that was picked (rare on systems like the xbox, more of a thing for 16 bit consoles and older). Time to find the real data the game uses.
