I have a client who sold her commercial property subject to an installment agreement. California has Form 593 Real Estate Withholding Tax Statement which requires her to remit a payment coupon and a paper check to Franchise Tax Board every month for the next ten years of the installment agreement with a copy to the seller. These requirements are onerous for my 77 year old client. She can opt out and have 3 1/3% of the sales price withheld at close of escrow and forgo the monthly payments.  In this case can I report the full gain to California on the 2020 return but still report it as an installment gain for IRS?

Can't find anything written.

Denise Robertson