When does TOS charge their $0.65 contract fee?

You will be charged $0.65 PER LEG anytime your BTO, STO, BTC, STC order gets filled. The commission is only $0.65 cents, no contract multiplier needed. For example:

1 contract of a vertical credit spread: STO + BTO + BTC + STC = 0.65 x 4 = $2.60