Cell styles

[Formula11]

If I create a new style in Excel, what is the best way to ensure that style formatting applies ALL of the time.
Before being aware of styles, I would select all cells and change colour or font, but during insertion of rows/columns, often the formatting would revert back to the "Normal" style.
Is there a setting which ensures this won't occur?

 

[Formula11]

For example, if I merge cells in the new style, and then unmerge, the style for all but the first cell goes back to "Normal".

 

[Formula11]

Bumping up.