I have a custom module which assists with creating inventory purchase orders.
- Takes past 30 days sales to get daily sales average for each product (by SKU, not product ID)
- Takes account of "combination" products where 'Product A' is really a combination of 'Product B' and 'Product C' we disregard product A and count those sales towards both B's and C's sales for finding our purchasing need.
- We assume a 30 day turnaround time, and anything under 60 days of stock needs reordering, under 45 days needs urgent reordering.
- Reorder quantity is calculated as ((daily sales average)*(60))/(current stock qty)
The module is now proving to be too simple for our needs. We need several modifications made:
We can't rely on just one set of sales figures for deciding a purchase ammount. se calculations are now proving to be insufficient since a number of things, such as running out of stock for weeks, can create misleading figures. Thus we need to look at multiple figures:
With those figures, we can then either use the highest number from the set, or account for growth rate if the numbers show consistent growth.
We also need to be able to enter in pending ammounts for those calculations. As in, if we have 50 pieces in stock and just placed an order for 25 more, we need to be able to account for those 25 pending items. This way we can keep track if our needs change during that 30 day turnaround waiting for inventory. Likewise, we need to be able to clear out those pending numbers when inventory arrives.