[eluser]jprateragg[/eluser]
Well, you have two options. You can extend the form_validation class (MY_form_validation) and modify the decimal function, or you can create a helper function, name it something like 'dec_len($data, $length), and call that function in the form validation rules. In your rules, you would reference it simply as "function[2]", the number being the number of digits after the decimal you require.