Amending three previous years for California for same reason with one cover lettter

[Matt18]

The past three years I had dividends that were exempt from California income, but I didn't properly tell TurboTax and it was not reflected on my state returns. The situation is the same for all three years, so I would like to send a single cover letter that explains the situation and shows the calculations. Is this ok? or do experts highly recommend three separate letters and cover letters?

[MonikaK1]

If you are going to amend your California returns because you identified that some dividends were taxed that weren't taxable in California, you would need to make the adjustment in the returns themselves and then complete California Schedule X. Answer the questions that appear and enter explanation where prompted.

See this help article for more information and steps.