Okay this has been resolved and it turns out that it was my own cock-up. When I was sending the details to Jenn, I noticed that one of the three items was already on sale. I feel like a fool now for something s simple. That explains the discrepancy in the discount.

I have now ordered all three items, with the July 4th coupon applied to the remaining two and all went well, so all is good. :)

Thanks to Jenn for her help.

@galaxiefilm
Strange, I use Firefox and PayPal and have never had a problem here, including tonight. But even if I did, I wouldn't touch IE with a disinfected barge pole, held by a robotic arm, whilst in a lead lined room, wearing the highest grade radiation and disease protective suit. LOL.