2017 error: Rental property incorrectly shows $22,044 in revenue; should be $20,400. Net loss would have been $1644 more. Worth fixing on our CA and federal returns?

[bartinspain]

What is the deiffernce in return for Californai and federal?  What does it cost to use Turbotax and to correct an old return?  

[Zbucklyo]

To first order, assuming you are able to fully deduct the loss in 2017, is $1644 * (your marginal federal tax rate + marginal CA tax rate).

If you have desktop for 2017, you just have to go back in and amend the return.  Cost is your time plus cost to mail the amended returns.