I think here that you need to consider the definition of "last edited".
A macro does not run  continually. If it did, a user would never be able
to interrupt long  enough to enter anything into a cell!
Macros are an "on-demand" kind of thing. Even the "Event" macros
are on-demand, it's just you've pre-defined or automated the "demand".

Conditional formatting, however acts ALMOST like a "Change" event.
(almost, but not quite, and the analogy fall apart very quickly, but still...)
So, if you have a macro that changes the color of a cell, the conditional
formatting says: "Look, the cell changed, what should I do?" and changes
it back as defined by the conditional format. Basically, the conditional format
acts as if it is applied almost continuously. screen refreshes, cell changes,
etc.

so.. if your definition of "last edited" means the last action that takes
place.. well yeah!
If your definition of "overrides" means something like "takes precedence"..
whell
that's probably true too... just for different reasons.

Kind-of like having two macros. One changes the cell to red, the other to blue.
the one changing it to red is called by just about every other macro, including
screen refreshes and selectionchange events. When you run the macro changing
the cell to blue, it stays blue until ANYTHING happens, then it changes back to
red.
So, in this case, the one changing it to red "overrides" any other change... and
it is the last (or most recent) action.

Another simple fact is that the "format set  my macros" is still taking place.
If you removed the conditional formatting, the cell will display  as the cell
format dictates.
Kindof like cutting a hole in the wall and haning a picture over it.
No matter how big the hole is, or what you put in the hole, all you see is the
picture.
Once you remove the picture, then you can see what's been going on with the
wall...

Hope this rambling narrative actually make sense...
Comes from caffeine difficiency... soon to be rememdied.