This method of storage charging is similar to the volumetric charging method but instead calculates storage on the total number of units held in stock for a period instead of needing product dimensions to be in the system.
To set this up, please navigate to Clients > Search for client > Edit and then select the storage cost tab or simply select the storage tab when creating a client for the 1st time:
Select the storage type to "StorageUnits" and then select the "storage cost frequency" - you can choose Daily, Weekly or Monthly.
This means system will calculate total units in stock for the frequency you select and then multiple it by your storage unit charge.
Please also make sure you tick the option "Automatically Calculate & Invoice Storage Costs according to frequency".
Now you can set a default storage unit charge for the client, please select the default tab and enter the default storage unit rate:
For more accurate charging - it is possible to enter the pricing as 3 decimal places i.e. 0.005 is 1/2 a pence
Please note the storage unit rate will depend on the frequency you select.
So for my example daily is selected as the frequency - so for every day that there is 1 unit in stock the system will charge £0.01
If there is 10,000 total units in stock for the client it will charge £100 per day, and so on.
The storage unit set above is a default amount that is used for all products for that client.
Unit Fee per Product
However if you wish you can select certain products to have a higher or lower storage unit amount to the default (if the products are much bigger or smaller than the normal size for that client).
Indeed to represent a true storage charge in relation to the size of the products - you can setup a different unit charge for every single product if you wanted to.
To do this, please navigate to Products > Overview then search and edit product. Then select picking / storage cost tab:
Now just enter the desired over-ride storage unit cost to be applied for that product and hit save.
Upload in Bulk
If you want to have a different storage unit rate for each product - it will be quicker to use the Product Upload update loader in Products > Extras
I have selected £0.25 so this product will get charged higher than the default client rate of £0.01 per unit per frequency.
The storage charge will now appear in unconfirmed invoice every time the frequency runs.
Check Current Storage
You can also check the current storage charge by navigating to Accounts > Overview > Calculate Current Storage
Change the calculation type to storage units and then confirm:
In my example i have:
SKU 1 = 64 units in stock x £0.25 = £16.00 (over-ride product unit cost of 0.25)
SKU 2 = 10 units in stock x £0.01 = £0.10 (client default of £0.01)