If you stayed at your old plan and just bought more GB as needed, they would be $10.00 each so your total monthly cost to manually get 15GB would be $99.99. 34 cents just makes everyone's life easier to live without a calculator in their hand at all times. If I had your address I'd send you the $8.16 for the entire life of your contract just to make you happy. Your math did not weigh-in on the ratio of data-to-bill when the modem lease is added to the monthly total, making an ever-so-slight improvement in your favor. I spare everyone the petty details. 34 cents won't buy a postage stamp, a month, so is it really worth complaining about? The perfect world everyone wants to live in isn't here yet.
It's market analysis. Just like my health insurance. Buying insurance from my employer for my wife and myself (Self Plus One) costs 130% more than buying insurance for just myself. It should only cost 100% more to add my wife.
When exede first launched, the lowest plan was 7.5 GB @ $49.99/month.
They upgraded that plan to 10 GB at no extra charge. That is why the
disparity in pricing, you were really paying for 7.5 GB but getting 10
GB out of the deal.