What is the burden of sustaining a motion on grounds not stated by the lower court?

The question which presents itself is: Should the successful movant who wants to support the order have the burden of sustaining it on grounds not stated by the lower court? In Mercer v. Perez, supra, the court stated: 'The second purpose of this requirement (the specification of reasons) is to make the right to appeal from the order more meaningful. While the rarity of reversals is doubtless due to the circumstance that discretion is not often abused, it must be recognized that under the prior law an appellant challenging an order granting a new trial tended to have great difficulty in presenting his case. It often occurred, for example, that the notice of motion was predicated on all or most of the statutory grounds, and the subsequent order specified neither the ground or grounds found applicable nor the reasons therefor; in that event, the appellant was left in the dark as to which aspect of the trial to defend, and quite understandably struck [260 Cal.App.2d 377] out

Page 264