I posted this response on another forum in support of the question which was asked regarding flex. His question was simply, why when I drag an external audio region in ( in this case it was create by another user, using logic at a different tempo), if the project tempo doesn't match - when I turn flex on the region immediately gets longer or shorter to conform to the project tempo. He just wants the current project tempo in conjunction with audio region to work as if he recorded the region into logic at the current global tempo.... My contribution: This flex stuff is making me crazy too. Between Detect tempo, analyze transients, analyze audio for flex editing - I can't figure out what flex is doing when and where, and what is related to each other in terms of each function doing the same thing or different. So to your point ( and I wish there was a white paper or something on how flex works internally ) - ( and I am not talking about flex markers, but rather the global tempo and interaction with a flex enabled region). Detect tempo used to enable "Follow tempo" for audio not recorded in Logic, now in 10.2.1 the only option appears to be flex. But as you stated and screen shot below demonstrates - there seems to be something a muck or a general lack of understanding certainly on my part. I think just some basic assumptions and rules on how it all inter-relates would save a ton of frustration... One example and in support of the OP ( I went the opposite though where may project tempo was set high - intentionally)..... I dragged in two audio files not recorded in Logic. Both songs are substantially bellow the current project BPM. I enable flex on one and the region speeds up to match the project tempo ( I assume Logic tries to determine the BPM of the audio based on the transient detection it does when enabling flex and then adjusts based on the project tempo. On the other region same exact thing.. except it doesn't move and plays back "apparently" at recorded tempo, not of the global project BPM..... I did nothing except drag both these files in and enable flex.....(flex pitch or flex time - makes no difference) In support of the OP - I too would very much appreciate anyone who knows what is going on and can explain it?