Legal Question in Business Law in California

What you describe is allowed under the law. CCP Section 94(b) allows the plaintiff to take a deposition and that is separate from the Rule of 35. CCP Section 94 does not limit the document requests that can be made for production at a deposition.

The rule of 35 only exists to prevent a party from drowning another party in a bunch of written questions that have to be answered in writing, when the much more efficient methods of reviewing documents and taking oral depositions can be used to gather information. Therefore those methods are much less restricted and do not come under the rule of 35 in order to encourage their use as opposed to written interrogatories.

It's also possible to ask the court for permission to exceed 35 questions. Such permission is more or less routinely granted in complex unlimited civil cases, but I think a judge would be much less inclined to allow more than 35 questions in a limited civil case.