Cell format crosstalk

[Walter Briscoe]

I am running Excel 2003.
I have a cell whose Format is controlled by Conditional Formatting.
If I change the Font for some characters, I get curious effects.
If, say, I start with 7 characters with applicable format F
FFFFFFF and set the format of 2 characters to G, I expect to see
FFFGGFF.
Instead, I see
FFFGGZZ, where Z is the default format.

I am sure I am not the first to see this behavior.

Can someone please supply references?

I think I need the pseudo-code:
1) Find applicable conditional format;
2) Copy that format;
3) Delete all conditional formats
4) Set the format for the start characters to that copied;
5) Set the modified format for affected characters;
6) Set the format for the remaining characters to that copied.

All I want to do is
C.Characters(start:=Start, Length:=Len).Font.Size = 14


if anyone has working code, I am happy not to reinvent the wheel.