Amazon Giving Weird Discounts

[MvRojo]

So I placed an order for several BDs, and Amazon mysteriously gave me 10% off + a $5 discount.

Item(s) Subtotal: $139.45
Shipping & Handling: $6.94
Promotion Applied: -$13.95
Promotion Applied: -$5.00
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Total Before Tax: $127.44
Estimated Tax: $0.00
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Grand Total: $127.44

The weird part was that when I toggled it to Super Saver Shipping, all those discounts disappeared (and then re-appeared when I switched back to standard shipping).

Is this happening to anyone else?

EDIT: Hmm, I tried this again with a few different movies. After toggling back and forth, this time I was able to get Super Saver shipping and the $5.00 off.

Item(s) Subtotal: $48.97
Shipping & Handling: $4.96
Promotion Applied: -$5.00
Super Saver Discount: -$4.96
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Total Before Tax: $43.97
Estimated Tax: $0.00
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Grand Total: $43.97