High utilization of your total available credit is bad for your score, but so is zero utilization. For the optimal score, you want to let a small balance report.
If paying off that Amex left all of your accounts at zero balance on your report, that is the likely reason for the small score drop.
Starting: EQ 622 (myFICO 7/7/12), EX 696 (TU FAKO 8/14/12), TU 621 (CK TransRisk 7/24/12), Total CL $1k on 2 TLs
Current: EQ 709 (CCT 2/4/15), EX 704 (CCT 2/4/15) , TU 702 (CCT 2/4/15), Total CL $110.3k on 14 TLs Goal: 740+ x3
My Wallet: Amex BCP $30k, Chase United Explorer $16k, Amex SPG $13.5k, Barclaycard Ring MC $12.5k, Chase CSP VS $12.2k, Discover it $10.5k, C1 Venture VS $6.5k, Chase Slate $3.5k, Amex Hilton Surpass $2k, Barclaycard Apple V $2k, Chase Freedom V $1100, BoA Cash Rewards V $500, Citi BestBuy $500
My Loans: Prosper $25k/36mo, Prosper $17k/36mo
My Business: Chase Ink VS $5k, Amex BRG NPSL (> 10k),
