There’s bound to be someone who comes up with a better answer than this but I’ll give it a shot as I understand it.
We are all required to interpret the legislation (so the Adelphi keeps reminding us) as we understand it.
Usually we all agree on how it should be interpreted. On occasion our interpretations are challenged.
Case goes to Commissioners or beyond and a different interpretation is reached by said court.
Paragraph 18 of Schedule 7 of the Child Support, Pensions and Social Security Act says that when that happens we don’t have to go and trawl through all our caseload to find cases where we applied the wrong interpretation in the past. If a case was down as a look-alike then we can go back and change it in line with the lead case but otherwise we don’t.
In a nutshell, that is the anti-test case rule.
Sometimes a Commissioner/Judge will say the rule doesn’t apply. That is the gist of what Peter Barker was saying at the end of this thread
Out of Date cheques