Because Premium has more forms than Deluxe. It is an upgrade. The additional $103 is only the difference in price you have to pay. As I said above the full price for Premium is $129 for federal and $64 for state (Total $193). Deluxe doesn't have 1099B for sales, K-1 or self employment income. See which forms are included in each version......
https://turbotax.intuit.com/personal-taxes/online/free-edition.jsp#tax-forms
Yes you can consider it an "add-on" or you can start out in Premium. It is just a higher version. Why did you pay for Deluxe in April if you weren't filing yet? You don't have to pay for Online until you file or want to print. Or are you amending a filed return to add other income?
