In BIFF files, rows and columns are always stored 0-based, rather than with an offset of 1 as they appear in a sheet. For example, cell A1 is stored as row 0 (rw = 00h), column 0 (col = 00h); cell B3 is row 2 (rw = 02h), column 1 (col = 01h), and so on.
In most cases, you can use the variable-naming conventions in this article to determine if a variable is 0-based. Variable names that begin with the letter i are usually indexes, which are 0-based. For example, the variable ixfe occurs in every cell record; it is a 0-based index into the table of XF records. Variable names that begin with the letter c are usually counts, which are 1-based. For example, many records contain a cch, which is a count of characters in the following string.