sc.judiciary.gov.ph/jurisprudence/2013/june2013/169214.pdf
Remedial law; "laws of the case" vis-a-vis "res judicata" explained -
"x x x.
Law of the case has been defined as the opinion delivered on a former appeal. It means that whatever is once irrevocably established the controlling legal rule of decision between the same parties in the same case continues to be the law of the case whether correct on general principles or not, so long as the facts on which such decision was predicated continue to be the facts of the case before the court.21
We point out in this respect that the law of the case does not have the finality of res judicata. Law of the case applies only to the same case, whereas res judicata forecloses parties or priviesin one case by what has been done in another case. In law of the case, the rule made by an appellate court cannot be departed from in subsequent proceedings in the same case. Furthermore, law of the case relates entirely to questions of law while res judicata is applicable to the conclusive determination of issues of fact. Although res judicata may include questions of law, it is generally concerned with the effect of adjudication in a wholly independent proceeding.22
The rationale behind this rule is to enable an appellate court to perform its duties satisfactorily and efficiently, which would be impossible if a question, once considered and decided by it, were to be litigated anew in the same case upon any and every subsequent appeal. Without it, there would be endless litigation. Litigants would be free to speculate on changes in the personnel of a court, or on the chance of our rewriting propositions once gravely ruled on solemn argument and handed down as the law of a given case.23
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