Description
This contribute Quantity Base Discount as opencart plugin to extend the opencart avaibility to auto discount when cart quantity reach the preset limit.

Features
Flat rate or multiple ranges base discount
Allow date schedule to trigger discount promotion
Multiple Geo Zone supported

Example
Flat Rate Discount
Discount Rate : 5
total = subtotal - 5

Range Base Discount (%)
Discount Rate : 5:5%(quantity:discount) , 10:10%(quantity:discount)
If cart quantity < 5 then 5% applied, If 5 < cart quantity < 10 then 10% applied
total = subtotal - subtotal(5%)

Range Base Discount (fixed rate)
Discount Rate : 5:5(quantity:discount) , 10:10(quantity:discount)
If subtotal < 5 then -5 applied, If 5 < subtotal < 10 then -10 applied
total = subtotal - 5

Easy Install
1) Unzip and upload the contents to the root directory of your OpenCart installation
2) Logon to administrator page, goto 'Admin->Users->User Groups->Edit the Top Administrator'.Then find and check the total/quantity_base_discount for both modify and access. Save.
3) Logon to administrator page, goto 'Extensions ->Order Totals -> Quantity Base Discount'.
4) Install the module, and click edit to configure.
5) Adjust the Sort Order before the Total.Save.

Note : The calculation does not included tax deduction.