I use 2002 but also used 2003 briefly. The question is do you really want to create extra fields for an exception such as this which will only be used for a few contacts? I can see the need for a second mobile field but four? How about:
1. Entering the contact twice with last name fields such as "Last Name (Home)" & Last Name (Business) or use the Company Name to differentiate between the records. 2. Enter the surplus numbers in the notes field. 3. Use the second Business and Home fields - the number will appear obvious as a mobile number.
If you really want to create more fields click here