The cells in the right column of the table shown in figure 4.5 have different leading or padding. Observe that the default leading of the content of a cell in text mode is equal to the font size. Internally, the leading is set like this: This is different from the default leading of a Phrase object outside a PdfPCell.
There can be a lot of differences between a UDF and stored procedure, as the prior link has shown. Another difference is the UDF can be directly selected from, whereas a stored procedure requires one to insert the results into a tempory table or table variable.
A stored procedures is a pre-defined, reusable routine that is stored in a database. SQL Server compiles stored procedures, which makes them more efficient to use. Therefore, rather than dynamically building queries in your code, you can take advantage of the reuse and performance benefits of stored procedures.