KITs are made up of two or more components.
The stock levels are changed at the individual product level.
Example
Your kit is a Computer Set.
Your kit is made up of 4 variants:
1 Keyboard
1 Monitor
1 Mouse
1 Laptop
Current inventory levels for the 4 variants are:
10 Keyboards
7 Monitors
5 Mice
6 Laptops
This means, you currently have 5 Computer Sets "On Hand" & "Available" in your inventory because you need the quantities of each of the 4 variants to make 1 Computer set. The limiting variant is the 5 mice, you can have a max of 5 Computer Sets.
Lets now assume that you got an order for 3 Computer Sets.
Each of these variants will reflect the changes from that order. Your available stock will be adjusted to the following:
7 Keyboards
4 Monitors
2 Mice
3 Laptops
You will notice that your Computer Set stock will show 5 On Hand but only 3 Available since 2 were Allocated to the sales order.
Now, let's say you receive a sales order for 1 mouse. Once you "Confirm" the order, inventory availability will decrease by 1 as inventory allocated increases by 1.
Now, you will only have 1 Available Computer Set.
Altho you haven't committed a whole Computer Set, the limiting variant mouse has only 1 qty available now which will make Computer Set availability to 1.
If you receive an order for 1 Keyboard, you will notice that the availability of the Computer Sets will not change since there is enough stock to meet the maximum number of available Computer Sets.