Enter/Match Partial Cost Modification - Inventory versus General Ledger Test

Balancing General Ledger against Inventory has always been a tremendous headache. I have always spent several weeks handling Inventory-GL issues which theoretically would not take more than few days. The problem in our case is represented with "cost-adjustment" primarily which results from improper application of certain processes.
This headache has motivated me to create a sort of test-environment in order to detect all the associated factors affecting the IV-GL balance. Aside from the issues resulting from the improper application (which is not my topic now), I have found out that there is a specific case in MS Dynamics GP 10, in which the system contributes to the IV-GL imbalance, which might be called  "Enter/Match Partial Cost Change".  I will thoroughly explain this point as follows;
Stage 1 - Receiving a Shipment
Receivng Transaction Details:

Document Number	Type	Item	Quantity	Unit Cost	Extended Cost
RCT000000889	Receiving	A	100	39.25	3925

Inventory Module:

IV30300

Item	TRXQTY	Unit Cost	EXTDCOST	IVIVINDX	IVIVOFIX
A	100	39.25	3925	Inventory Warehouse	Accrued Purchases

IV10200

Item	QTYRECVD	Unit Cost	EXTDCOST	ADJUNITCOST
A	100	39.25	3925	39.25

SEE30303

Item	TRXQTY	Unit Cost	EXTDCOST	IVIVINDX	IVIVOFIX	JRENTRY	Dr	Cr
A	100	39.25	3925	IV Warehouse	Accrued Purchases	X	3925	0

General Ledger :

GL20000

JRENTRY	Account Index	Dr	Cr
X	Inventory Warehouse	3925	0
X	Accrued Purchases	0	3925

Stage 2 - Enter/Match Invoice:
On the Enter-Match winodw, I will suppose that part of the shipment will have the same Unit Cost (regardless of the quantity), while the other part of the shipment cost will increase or decrease (same result either in the increase or decrease.)

Enter/Match Transaction Details: 

Document Number	Type	Item	Quantity Invoiced	Unit Cost	Extended Cost
RCT000000890	Invoice	A	80	39.25	3140
RCT000000890	Invoice	A	20	50	1000

Inventory Module:

Inventory module assumes that all the cost layer is adjusted to have a unit cost of (50).Therefore, it calculates the difference between the old Extended Cost (100*39.25 = 3925) and the new Extended Cost (100*50 = 5000) and the difference between the two which is (1075) is debited on the inventory warehouse account.

IV30300

Item	TRXQTY	Unit Cost	EXTDCOST	IVIVINDX	IVIVOFIX
A	100	39.25	3925	Inventory Warehouse	Accrued Purchases
A	0	0	1075	Inventory Warehouse	COGS

IV10200

Item	QTYRECVD	Unit Cost	EXTDCOST	ADJUNITCOST
A	100	50	3925	39.25

SEE30303

Item	TRXQTY	Unit Cost	EXTDCOST	IVIVINDX	IVIVOFIX	JRENTRY	Dr	Cr
A	100	39.25	3925	IV Warehouse	Accrued Purchases	X	3925	0
A	0	10.75	1075	IV Warehouse	COGS	Y	1075	0

General Ledger :

On the other hand, General Ledger can detect correctly that the change on the unit cost is partial, while the other part of the cost layer still have the same cost. Therefore, it calculates the cost adjustment as follows;

Old Extended Cost = 100*39.25 = 3925

New Extended Cost = (80*39.25)+(20*50) = 4140

And the difference is 4140 – 3925 = 215

GL20000

JRENTRY	Account Index	Dr	Cr
Y	Inventory Warehouse	215
Y	Accrued Purchase		4140
Y	COGS	3925

This test has been applied by MVP Mohammad Daoud on GP 10.0, 2010 and 2013 with the same results returned. The good news is that the new utility in GP 2013 "Reconcile to GL" locates this difference as shown below;

Reconcile to GL Utility - GP2013

As a result of the explanation above, GP creates an imbalanced Journal entries between GL and Inventory in this case specifically (partial change of the unit cost) because of having different modules behaviors.




Best Regards, 
Mahmoud M. AlSaadi