Each of the three credit reporting bureaus---Trans-Union, Equifax and Experian---use the FICO scoring system in slightly different ways from each other.
Maximum scores are rarely ever reached by consumers. And all this talk on the internet of aspiring to achieve such a goal is---IMHO---a lot of hot air. What counts is a decent credit history. If a consumer has 3 to 5 accounts open and active for at least 2-5 years, owes less than 50% of available "revolving" credit, pays on time and has not outstanding derogatory accounts (collection accounts, chargeoffs, judgments, etc), that consumer will have an excellent credit score.
If you're thinking of buying a home, first step is to get Prequalified by your Local Mortgage Banker. Your Mortgage Banker will review your Income, Assets, and Credit---including a free FICO score credit report---to determine which programs and maximum loan amounts you'd qualify for.
MyFICO.com is the best source for accurate information on the mysteries of the credit scoring "Secret Family Recipe."