When the deal was $10 it rang up as $10. There is no reason to ring up each item individually, that's not how it works anyhow. It's also not a discount, it's just how they do a deal. A deal they've been running for years. Having ordered before when it was $10 it was always rung up as $10. That individual location needs to be called out for that (and any other ones that do it). They now have "starting at" instead of a flat amount with limited menu options.
For example if I were to order it right now (with the deal having increased to $10.99)
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I just priced out one for example's sake where it was a $10.99 option and here's how it looks online:
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Beverage randomly selected as Dr Pepper, App randomly selected as Chips and Salsa and entree chosen for ease sake a $10.99 option.
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So either the PP didn't order items that were on the particular menu for the deal OR the server incorrectly rung it up.