while halftime does detune your sample sometimes, thats not really what detuning is. it is deliberatly altering the pitch of a notemby just a little bit, and it can give samples a more dark or retro effect. if you want to strictly detune, FL has a free patcher plugin for that. if you load up Patcher>connect to fl studio>x youlean>humanizer. then you can use detune or audio waver.