If your invoice is not added with the correct date and time, it can lead to incorrect consumption data. To have a complete understanding of its impact, you only need to know two things:
1. Your consumption between two inventory sessions is calculated as follows:
Consumption = Total Items (Beginning) + Items Received - Items (End)
2. WISK uses the date/time that inventory was started for all calculation purposes
Wrong Invoice Date
If an invoice added on the wrong date, it may not fall into the correct inventory period. It is very important that the invoice be sandwiched between the right dates so that the Consumption calculation above contains the correct values.
Wrong Invoice Time
The same issue can arise when adding an invoice on the same date as an inventory session.
Since WISK uses the inventory's Start Time to determine when it occurred, it will make a difference whether the invoice time is before or after the inventory has started.
For these instances, we recommend leaving your received stock to the side, doing your inventory (while excluding these new items), then adding the invoice after the inventory has been completed.
Let's say for a given week, you start off with 10 units of an item, receive 6 units from an invoice, then count 9 units the next time you take inventory. Based on the Consumption calculation, you should have consumed 7 units.
10 (beginning) + 6 (received) - 9 (ending) = 7 units consumed
If your invoice with the 6 units was entered at the incorrect time (at a date/time outside of the inventory period), the consumption calculation for the period will look like this:
10 (beginning) + 0 (received) - 9 (ending) = 1 unit consumed
The resulting consumption will be too low for the period that was supposed to contain this invoice and it will be too high for the period that now mistakingly contains this invoice.
Negative Consumption / Stock Error
Whenever you see Negative Consumption in your reports, it is either due to miscounts or misdated invoices.
If you take the same example as above, but start off with 7 units, look what happens to your consumption when an invoice is not added correctly:
7 (beginning) + 6 (received) - 9 (ending) = 4 units consumed
7 (beginning) + 0 (received) - 9 (ending) = -2 units consumed