The rendering of the text in MS Office is made by some internal methods. It is not the same as in Winforms (GDI+ (Standard, Typographic), GDI (WYSIWYG)), in Wpf or in Flex.
If the line spacing is not changed then at default value and much text the last line can go out of the cell and will cut in MS Word.
To solve the issue we added next options that normalize line spacing and prevents cutting of the text.
StiOptions.Export.RichText.LineSpacing = 0.957;
StiOptions.Export.Word.LineSpacing = 0.965;
The options could be set to 1 only if you use Use Page Headers and Footers option of the export. In this mode the Height of the cell is not set and it is changed to fit all text.