Yes, you can upgrade your version of TurboTax and only pay the difference. Your information will transfer to the Premier version once you upgrade.
How do I upgrade my TurboTax for Windows software?
Upgrading is a one-way street. Once you've upgraded, you can't downgrade back to your original version.
- With your return open in TurboTax, select Upgrade TurboTax at the very bottom of your screen, towards the right
- In the new window, select the version you'd like to upgrade to and select Upgrade Now
- Follow the onscreen instructions to purchase the upgrade
- When finished, continue working on your return. You don't have to go back to the beginning
https://ttlc.intuit.com/community/upgrading/help/how-do-i-upgrade-my-turbotax-for-windows-software/00/26238
How do I upgrade or switch to a higher version of TurboTax Online?
You can upgrade or switch to a higher version of TurboTax after you've started your 2021 return.
To upgrade your version of TurboTax:
- Make sure you’re signed into TurboTax and have opened your return.
- If you don't see this option, select Upgrade from the menu.
- If you don’t see the menu, select the menu icon from the toolbar.
- Select the version you'd like to upgrade to.
- We'll prompt you to pay if you want to print or e-file your taxes. You can also prepay at any time:
- Select File from the menu. (Don’t worry, you don’t have to file taxes—this just gets you to the payment section.)
- Select Start or Revisit next to Review your order.
- You’ll see a summary of your order. Select View payment options.
- Keep going until you see How would you like to pay for TurboTax? On that screen, select Pay with Credit Card.
- Enter your credit card information and select Continue.
Once you’ve paid you can go to Tax Home to access your upgraded features.
https://ttlc.intuit.com/community/upgrading/help/how-do-i-upgrade-or-switch-to-a-higher-version-of-turbotax-online/00/26239