If a party has timely served a Demand for Simultaneous Exchange of Expert Trial Witness Information pursuant to Code of Civil Procedure section 2034.210, then “all parties who have appeared in the action shall exchange information concerning expert witnesses in writing on or before the date of exchange specified in the demand.”C.C.P. §2034.260(a). Unless there is a court order specifying otherwise, that date for the simultaneous exchange is 50 days before the initial trial date, or 20 days after service of the demand, whichever is closer to the trial date. C.C.P. §2034.230(b).