I have the following formula written to score opportunity records. 

IF( Total_Qualification_Score__c <= 15, "Highly Unfavorable",
IF( Total_Qualification_Score__c <= 23, "Unfavorable",
IF( Total_Qualification_Score__c <= 35, "Moderate",
IF( Total_Qualification_Score__c <= 47, "Favorable",
"Highly Favorable"))))

Problem is, I get the following error:

Error: Compiled formula is too big to execute (9,664 characters).

Apparently this is because the Total_Qualification_Score field is also a formula.  SFDC Help Desk could not help me resolve this issue and suggested I post to this discussion board.  Thoughts?