ok i read other post in JJOSXL request thread and will continue here. You state that the loops goes out of time after loping a while using the audio track that you recorded. Ok i understand this and see why you have problems.You or MPC wont be accurate enough, IMHO to loop infinitly in time. 1/44000th of a second is all it takes to go out of time eventually. So your method is kinda self defeatist.
It is good in the fact that it kinda works but not the best way ok. Point is you will never get a sample to loop perfectly unless you cut a perfect loop, even then it might be a perfect loop but it might not match BPM.

See so you are painting your self into a corner. I know you want to keep your workflow fluid yes, but investing a little time will save you hours of angst ok.
Two things i suggest straight up is yes record as normal to your sequence to audio track. This way it is close to your BPM. Next comes the work sorry but that is the nature of the beast that is the MPC.
Assigning a sample to a pad and looping it is not the way to go really, nor audio track either as its gonna be impossible to make it tight enough, unless you get lucky. So here is what you can do. For starters, record your sample to audio track. trim sample and then turn on loop. First you should make sure loop is set correctly otherwise following wont work. Do not worry about BPM yet. Get it looping so it seems right. Next turn off the loop in the trim window and assign sample to a pad. Make it mono, not poly, make it ONE SHOT, now go to begining of a new sequence and record pad hit that has sample you want to loop. Sequence should be same amount of bars and looping. Right now play it. If there is a gap between end and start of sample you must make BPM faster, if they overlap, make BPM slower. Again because of BPM only being to one decimal place, some samples will be close but not perfect. Thats ok though, as you will see.
So now you have a sample thats not looped but in a sequence that plays sample and its looping for you. Look at BPM, when sequence plays the sample so it loops correctly. this is BPM of sample. it should be close to what you origanaly recorded, but now its a working as a loop, but not in time right. Using sequencer like this means you can find the BPM to any looped sample, and it will never go out of time. But I know you dont want to use sequencer for loop right, you want to loop sample in time then what you are doing wont really be acurate enough. Do above method to find real BPM and then make it a patched phrase, thats why you need BPM. This will mean your sample will be able to match any BPM, and stay in time. Use Auto Chop as oppossed to normal chop. MPC is not really a phrase sampler as such and i think you are trying to use it as such. I now its a bit of work, and oh its gonna kill your workflow, but im sure out of time loops are killing your workflow a lot more than above method, which does not take long and will help keep stuff in time.
So chop it patch phrase it or use sequencer. In fact i can think of a another method, but i would be here all day and night. let me knowhow you go. try above and i rekon you will be amazed how tight it will be