In APP10 your choices are Null, Per Line, Per Amount, Per Weight and Per Volume. 

Distribute Charge By: 
If a default value has been selected for the charge type in the Purchase Charge Types window, it will be displayed here. You can change the value if needed. Possible values are: 

*Null (no value is specified): No distribution of charge costs among purchase order lines.
*Per Line: Each purchase order line will have an evenly distributed amount of the charged cost.
*Per Amount: Each purchase order line will have a charge cost proportional to the total purchased value per line compared to the total order value.
*Per Weight: Each purchase order line will have a charge cost proportional to the weight per line compared to the total order weight. 
*Per Volume: Each purchase order line will have a charge cost proportional to the volume per line compared to the total order volume.
Note that if you specify a value in this field, you cannot enter any information in the Connect to Line No and Connect To Rel No fields.