Personally I like the proposal as written. I got most of what I intended in time, but think this would show excellent goodwill towards everyone who did actually participate, which is vital for maintaining a strong community and KEEPING new community members. Even those who this does not affect directly will see how the company operates, which I consider to be above and beyond compared to any other project/game company out there. I personally experienced a UI bug in my second purchase where the voucher entry box was 'stacked' behind the other boxes and unaccessible (I was actively looking for it during the second purchase).
I might also recommend a buy limit cap for events like this, as has been done before with great success (ie waka, license pre-sale, both of which limited the purchase to one item per click/transaction). Allowing the 'max level' per transaction/click in a case like this would be ideal imo... ie in this case the 'top level' was 2K packs, so allowing only up to 2K packs per transaction would be an excellent way to meter such a sale and offer more opportunity to more participants.