Font Object Settings
When you set fonts for the sheet, you are setting properties for the Font object. The Font object provides the following properties:
The fpSpread control, when applying fonts to cells, looks for the first setting of the Font object, and then applies that setting. This can result in settings being applied in a way you might not expect.
For example, if you set the font for a block of cells to be bold, and the first cell in the block is already bold and underlined, the rest of the cells in the block will become bold and underlined, because they are looking at the setting of the Font object for the first cell in the block.