Fixed Price Discounts Issue

[MrDerp]

I'm having problems offering any of my customers coupons as, no matter what I try, I encounter bugs that render the coupon system unusable. 

 

My latest issue is with fixed price discounts. I want to set up a coupon offering a £100 discount to an important client of mine. However, no matter what parameters I use in the coupon admin screen, it just isn't working properly.

 

Here is what I have tried:

 

1) I have added 2 products into my basket with a total value of £100. This value includes VAT @ 20% - the value before VAT is therefore £83.33, with a tax value of £16.67.

 

2) The appropriate discount code is then applied. This should result in a grand total of £0 (£100 - £100). However, what I am presented with is a value of £16.67 (i.e. the tax amount). 

 

3) I then increase the value of my order to £150 (£125 + £25 tax) and again applied the £100 coupon. This left me with a remainder of £50. So, in this instance, the coupon DID apply to the tax component. 

 

The coupon itself is set to apply to all products. Strangely, the coupons behave completely differently when specific products are assigned - it takes £100 off EACH product - is this by design or just another bug?

 

The way in which tax is handled differs depending on the parameters too. Sometimes the discount includes tax, sometimes it doesn't (I seem to recall when using percentages it doesn't include tax, but with fixed value it does...)

 

I have raised a number of issues with the support team in the past regarding the coupon system as, quite frankly, this module needs a rewrite as it is littered with problems. However, they have been unwilling to look into these issues and when pushed for the reasons behind this, they just ignore my emails.

 

Thanks in anticipation.