There are 3 GL Determinations used:
1. Item Group
By far the most common, this categorizes all items with this particular item group in to using the same GL determinations throughout. For example, each stage of WIP items would have its own GL Determinations, raw materials would have a separate one, merchandise yet another set, etc. Every time a new item is created, it's simply attached to this group and the correct GLs will automatically be posted. The GLs listed on this item group are used regardless of any other factors such as which warehouse the item is sold out of.
2. Item Level
Although less common overall, this one is much more common when it comes to non-inventory items since all non-inventory items aren't usually grouped in to one category. For example, non-inventory brewing equipment would want to hit different GLs than non-inventory restaurant equipment or non-inventory sales expenses. Item Level is also used sometimes for merchandise items if different GLs are used depending on which warehouse an item is sold from (sold from the brewery vs sold from a tasting room).
3. Warehouse Level
This one is rarely used as it would mean the first two options are ignored and instead the GLs to post to are determined on a per warehouse basis. For example, if you sell finished goods out of A1 it will post to the same GL as raw materials sold out of A1. Although you have the ability to, for example, choose "warehouse" level for finished goods and "item group" for raw materials to avoid this, you must be very diligent and fully understand how these 3 determination types work in order to ensure you do not negatively affect your database.
If you go with Item Group, you can see the Item Group listed on the 5th row from the very top of the Item Master Data window confirms FinGood: Bottled as the Item Group this item is associated with. Clicking the gold arrow next to FinGood: Bottled confirms which GLs are used:
If you change it to Item Level, the group of accounts above will be ignored and the GL accounts must be edited/confirmed in the warehouse section of the Inventory Data tab instead (see highlighted below):
If you use Warehouse level instead, the two options above will be ignored and instead will use the GLs associated per warehouse. You can click the gold arrow next to the warehouse and then click on the Accounting Tab to see the GLs associated with it:
In this case, the warehouses all have -99 system accounts to post to so not only would this warehouse need to be updated, but all other warehouses in the database would need to be reviewed to ensure the -99 accounts aren't used.