In a table B5-T30 (partially filled at present) conditional formatting is
applied - to highlight under performance - with conditions 1) =B5<B$4 and 2)
= B5 =B$4.

When the values in the range B4-T4 alter almost every time that works fine
for the latest figures.
However, all the earlier values should preserve the way they were displayed,
because the statistics remain valid relative to the circumstances at the time.

Would there be a way to attain this?