sokratis,

it's not a quantization thing,

it's all perfect till it has to repeat,
there is inconsistencies, some worse than others,

sp when you're constantly changing Variations, there's a lag, and it's noticeable,

maybe it's just a matter of the "markers" withing the audio, which tells it where to jump, is in the wrong place.

i do know that each style's audio drums is 1 continuous audio file, there is not one for A, one for B, etc