The rules are different for loans prior to 1998. Also, if the weighted average of your loans was 3% then that's what you got.
The interest rate for FFEL and Direct Consolidation Loans is set according to a formula established by federal statute. The fixed rate is based on the weighted average of the interest rates on the loans at the time you consolidate, rounded up to the nearest one-eighth of a percent. The interest rate does not exceed 8.25 percent. The consolidation rate is fixed for the life of the loan, which protects you from future increases in variable rate loans but prevents you from benefiting from future decreases in variable rates.
Borrowers with Stafford Loans issued on or after July 1, 1995, can reduce the consolidation rate by up to half a percentage point or more by consolidating before the end of the grace period.
If a borrower wanted to consolidate only Direct or FFEL Stafford Loans made between July 1, 1998 and June 30, 2006, the 2007-08 Consolidation Loan interest rate for loans that have entered repayment would be 7.22 percent. To consolidate those same loans during a grace or deferment period, the rate would be 6.62 percent. If a borrower consolidated PLUS Loans made between July 1, 1998 and June 30, 2006, the interest rate for the resulting PLUS Consolidation Loan would be 8.02 percent.
The interest rate you would receive, however, depends on which federal student loans are being consolidated. For example, your rate would be higher if you consolidated a 5 percent Federal Perkins Loan along with a 6.62 percent Direct or FFEL Stafford Loan"