It doesn't matter.
Even if you are creating a carry forward loss, that would need to be manually entered between products.
Your 2016 amended return be completed in TurboTax CD/Download; it will need to be printed and mailed.
Your 2018 tax return can be completed in either TurboTax Online or TurboTax CD/Download.
For more information on filing amended tax returns, follow these links:
What
to Include with Amended Tax Returns
How
to Amend
Tips
to Amend
IRS on 1040X