In the first decision, the court extended the one-week deadline, saying that doing otherwise would effectively nullify the part of the law that allows recounts. In the second ruling, the court ordered the Florida Secretary of State to accept the results of some of those manual recounts and ordered that Miami-Dade County resume a recount it had halted. When legislatures draft statutes, they do so without perfect knowledge of the future. They often leave gaps, and they create conflicts within their own statutes. It is the ordinary job of courts to fill in the gaps and resolve conflicts.
Courts have a lot of leeway in interpreting laws.
The first Florida Supreme Court opinion was not at all out of line with traditional statutory interpretation. J. Clark Kelso, professor of law at McGeorge School of Law, University of the Pacific. Once you say the seven-day deadline is not firm, that is rewriting the law. To set a new deadline is quite a reach. To the extent that one of the statutes provides for manual recounts, it is plausible to read it as meaning only those recounts that can be completed within seven days.