Simple Case
Inventory Simple Case - Avg Cost IS impacted by Sequence!!!
| 
| TxType | EFFCTV QTY | ACCUMQTY | COST | TOTCOST | ACCUMBAL | AVGCOST |  
| Beg Bal | 100 | 100 | 15 | 1500 | 1500 | 15 |  
| Sale | -50 | 50 | 15 | -750 | 750 | 15 |  
| Purchase | 10 | 60 | 20 | 200 | 950 | 15.83333333 |  | 
| TxType | EFFCTV QTY | ACCUMQTY | COST | TOTCOST | ACCUMBAL | AVGCOST |  
| Beg Bal | 100 | 100 | 15 | 1500 | 1500 | 15 |  
| Purchase | 10 | 110 | 20 | 200 | 1700 | 15.45454545 |  
| Sale | -50 | 60 | 15.45454545 | -772.7272727 | 927.2727273 | 15.45454545 |  | 
Inventory With Reversal - All Positive
Inventory with a sale reversal, but keeping it positive!   All good, but sequence matters
| Here, a purchase receipt comes between the +Reversal and -Sale record.
 
| TxType | QTY | ACCUMQTY | COST | ACCUMBAL | AVGCOST |  
| Beg Bal | 100 | 100 | 15 | 1500 | 15 |  
| Sale | -50 | 50 | 15 | 750 | 15 |  
| Purchase | 10 | 60 | 20 | 950 | 15.83333333 |  
| Sale | 200 | 260 | 15.83333333 | 4116.666667 | 15.83333333 |  
| Purchase | 10 | 270 | 20 | 200 | 15.98765432 |  
| Sale | -200 | 70 | 15.98765432 | 1119.135802 | 15.98765432 |  | Here, The +Reversal comes immediatelyh before the -Sale record.
 
| TxType | QTY | ACCUMQTY | COST | ACCUMBAL | AVGCOST |  
| Beg Bal | 100 | 100 | 15 | 1500 | 15 |  
| Sale | -50 | 50 | 15 | 750 | 15 |  
| Purchase | 10 | 60 | 20 | 200 | 15.83333333 |  
| Sale | 200 | 260 | 15.83333333 | 4116.666667 | 15.83333333 |  
| Sale | -200 | 60 | 15.83333333 | 950 | 15.83333333 |  
| Purchase | 10 | 70 | 20 | 1150 | 16.42857143 |  | If sale and reversal are together - it doesn't matter the sequence!
 
| TxType | QTY | ACCUMQTY | COST | ACCUMBAL | AVGCOST |  
| Beg Bal | 100 | 100 | 15 | 1500 | 15 |  
| Sale | -50 | 50 | 15 | 750 | 15 |  
| Purchase | 10 | 60 | 20 | 950 | 15.83333333 |  
| Purchase | 10 | 70 | 20 | 1150 | 16.42857143 |  
| Sale | 200 | 270 | 16.42857143 | 4435.714286 | 16.42857143 |  
| Sale | -200 | 70 | 16.42857143 | 1150 | 16.42857143 |  | 
Inventory With Sale/Reversal - Gets Negative
| Similar to the case where items were positive, the impact of matching Negative and Postive record have no net effect even when the accumlative qty goes negative:
 
| TxType | EFFCTV QTY | ACCUMQTY | COST | ACCUMBAL | AVGCOST |  
| Beg Bal | 100 | 100 | 15 | 1500 | 15 |  
| Sale | -50 | 50 | 15 | 750 | 15 |  
| Purchase | 10 | 60 | 20 | 950 | 15.83333333 |  
| Sale | -200 | -140 | 15.83333333 | -2216.666667 | 15.83333333 |  
| Sale | 200 | 60 | 15.83333333 | 950 | 15.83333333 |  
| Purchase | 10 | 70 | 20 | 200 | 16.42857143 |  | If a purchase comes between a negative sale and reversal, the ending avg. cost is impacted, but this is still perfectly acceptable and correct handling for the data given.
 
| TxType | EFFCTV QTY | ACCUMQTY | COST | ACCUMBAL | AVGCOST |  
| Beg Bal | 100 | 100 | 15 | 1500 | 15 |  
| Sale | -50 | 50 | 15 | 750 | 15 |  
| Purchase | 10 | 60 | 20 | 950 | 15.83333333 |  
| Sale | -200 | -140 | 15.83333333 | -2216.666667 | 15.83333333 |  
| Purchase | 10 | -130 | 20 | 2016.666667 | 15.51282051 |  
| Sale | 200 | 70 | 15.51282051 | 1085.897436 | 15.51282051 |  |