(a) Applicability. This rule applies to all proposals for settlement authorized by Florida law, regardless of the terms used to refer to such offers, demands, or proposals, and supersedes all other provisions of the rules and statutes that may be inconsistent with this rule. (b) Service of Proposal. A proposal to a defendant shall be served no earlier than 90 days after service of process on that defendant; a proposal to a plaintiff shall be served no earlier than 90 days after the action has been