Your analysis of how ACCPAC deals with different costing methods is incorrect.
If you received a machine at $500,000 and then a second machine at $550,000, your inventory would show 2 in stock and a total value of $1050,000.
Standard cost might still be $600,000. Recent cost $550,000. Unit cost $525,000.
When the first machine is sold the cost of sale results of different costing methods would be:
Weighted moving average - $525,000
FIFO - $500,000
LIFO - $550,000
Standard Cost - $600,000
User Specified cost - anything the user assigns.
The difference between average cost and the cost assigned to the sale must be accounted for in some way. In the LIFO, FIFO, and Weighted Moving Average costing methods, the remaining cost rremains assigned to inventory. So the sale of the second item results in:
Weighted moving average - $525,000
FIFO - $550,000
LIFO - $500,000
But under standard costing - $600,000 is also the cost of sale of the second item. This is clearly more than the total inventory value. But it must be accounted for.
The difference is sent to G/L as a cost variance. This variance credits expense for the value over and above inventory value that has been assigned as cost of sales. It assumes that other expenses are now being re-assigned as costs of sales.
In each and every case Softrak Sales Analysis would record the actual cost of sale assigned by ACCPAC.
Standard costing method is used to allow for assignment of costs not included in the inventory value. These might include freight, labor, storage, assembly, packaging, sterilization - all legitimate costs of the sale not included in inventory. Consider the following examples.
A manufacturer of the inserts for ball point pens would not find it economical to use manufacturing software to track the plastic, metal, and ink used and the hundreds of thousands of items produced in a day. Instead he would use overall purchases divided by how many thousands were made to calculate a standard cost, and monitor and change that cost periodically to reflect changes in the cost of raw materials.
A distributor of packing cartons is required by his customers to keep stock on hand so he can deliver to them at a moment's notice. The bundle that sells for $100 has a cost of sale that includes not only the bundle of cartons ($55) and the incoming freight ($1.00), which can be tracked through inventory, but also storage costs (1.25) and delivery costs (2.75), which are not even available until the time of sale. So he records the storage and delivery costs as expenses when the invoices from the public warehouse and the delivery service are received. He assigns a standard cost of $60. When the bundle is sold inventory is decreased by $55. The cost variance of $5 is a credit to expense that offsets the expenses already recorded, because these expenses are included in the cost of sales. Now he can calculate sales commissions on the real profit of each sale, which is $40, not $45.
Only when Standard Costing is not used as a costing method can the field "Standard Cost" be used to hold a benchmark value. Standard costing method may be the hardest to administer because it requires periodic review and adjustment of the value assigned based on the true total costs.
Manufacturers commonly use standard costing and manufacturing software typically includes provisions for tracking and recalculating costs in several ways to provide the information required to intelligently update the Standard Cost values.
If you find that commissions are being skewed by using this method, I would suggest that weighted moving average might be a better costing method for you to use.