What was the tax credit rate for residential solar in 2016?

was there a carryover limitation for subsequent years?

My client got a letter from FTB requesting proof of the solar expenditure, and questioning the carryover calculation.

Lacerte automatically limited the CA Solar credit to the amount of the CA tax for 2016, and then calculated the carryover to 2017,2018, & 2019.

I had not previously questioned how Lacerte was doing the calculation, and there does not seem to be any worksheet provided that outlines the application of the credit and carryover by year.

California is asking for that carryover calculation.

The Solar System Purchase in 2016 in the amount of $51,526

2016 original credit allowed on 540 (limited by CA Tax Due) was $7,056  (as filed)

2017 carryover credit allowed on 540 (limited by CA Tax Due) was $6,854 (as filed)

2018 carryover credit allowed on 540 (limited by CA Tax Due) was $4,170  (as filed)

2019 carryover credit allowed on 540 (limited by CA Tax Due) was $11,480

(2019 is not yet filed, but under review until I determine if these calculations were correct)

Is there anyone who can tell me if Lacerte is doing the calculations correctly?

I called and talked to several Lacerte specialists, who were unable to help me.  I may get a call back as the last one disconnected unexpectedly.

Can anyone help with this?