Are Pro versions of perks automatically applied when unlocked in the middle of a match

During a match, I saw the message "Assist Counts As Kill". I was using the standard Hardline perk which provides access to killstreaks one kill earlier. At the end of the match, the game informed me that I had unlocked the Hardline Pro perk which adds the bonus "every two assists count as one kill towards your killstreak." Is this what I saw earlier in the match or are there situations (i.e. you do 95% of the damage) where assists always count as kills?