Retained earnings (RE) at the end of the year is the beginning of the year (BOY) retained earnings plus the net income for the year minus any distributions of earnings for the year.
Most tax software computes the RE based on the amounts you entered for BOY RE plus the net income based on your revenue and expense entries minus your enties of distributions of earnings to shareholders.
TurboTax Business has that type of entry in the interview mode where BOY RE is entered and the rest is computed by the program.
If the end of year RE does not match your books that is a sign that not all the entries for the revenue and expense entries and your enties of distributions were done correctly.
I hope this helps for entering the RE in your Form 1120S.
What I am saying is that you do not enter the end of year RE in TurboTax Business.
The program will compute the net earnings for the end of year using the other items that you enter.
I opened my copy of TurboTax before I answered the first time in order to verify that is how it is done in the TurboTax program. You do need to enter the beginning of year RE.
I hope this helps to clarify for you.
So, you would include the current year net income plus the retained earnings from the prior year less any distributions for the year.
That is, combine the existing amount of the retained earnings and net income on the quickbooks balance sheet and put that combined total on the Schedule L balance sheet on the retained earnings end of year entry.
I hope this clarifies for you.