Question about MW2 Kill streaks?

My kill streaks are 3 for a uav, 4 for a care package and 8 for a emergency airdrop but lets say I get 6 kills and decide to call in my care package and I get a harrier strike that gives me a few kills.... It wont let me get my emergency airdrop unless I get 8 kills in a row with my gun. cus today I was 10 and still never got my emergency airdrop cus this happened and I want to know if this happens to anyone else. Like if im 6 -0 then get some harriers and it makes me 8 - 0 it still wont give me my airdrop unless I shoot 2 more people with my gun