Reward Points Module for ZC v13x

[countrycharm]

Hello, am I missing something simple?

Sub-Total : £20.00
Reward Points : -£10.00
VAT @ 20% : £4.00
Total £14.00


It should obviously be a total of £12 and with a VAT total of £2 where am I going wrong?

To be honest I don't know. I don't use the VAT part. Maybe someone else who is more knowledgeable can help.