When looking at inventory history for a product it will show, for example, +5 or -5 depending on if it went up or down from a transactions, etc. Instead of showing how much it went up or down, show the total quantity left after the action. This way we know how much quantity is still available at that time of change without having to reference the current quantity.

This is helpful if you ever need to track a product for any reason to see it's specific quantity during a period of time, either recent or old. If you try to see why an item did not move from a few months back, you couldn't even tell if it was out of stock or just not being purchased because it doesn't show existing quantity at that date.