When do all formulas of a listcolumn update?

I have the following formulas in a listcolumn:

=[@HR]*0,28
=[@HR]*0,28
=[@HR]*0,28
=[@HR]*1

When I change the last row to =[@HR]*2 then all formulas become updated so that:

=[@HR]*2
=[@HR]*2
=[@HR]*2
=[@HR]*2

I thought that this would only happen when all formulas were the sae and I changed one of them. But now they weren't all the same and Excel still went ahead and updated the entire column. This makes me feel unsure about Excel and life.

What are the exact circumstances under which Excel will update the formulas of a listcolumn?

EDIT:
This happened after I had run the following VBA code:

Application.AutoCorrect.AutoFillFormulasInLists = False
Intersect(rNewRow, lo.ListColumns("TB").Range).Formula = "=[@HR]*0.28"
Application.AutoCorrect.AutoFillFormulasInLists = True

It might have to do with that. But I don't know how so hope that anyone of you has an idea!