hello gG,
firstable, I hope you have received my email succesfully about the question you asked me privately.
to fully understand how 0Exy works, you have to fully understand how trackers work.
Songs are made of patterns. Patterns are made of lines.
Until now, everything is visible.
Now comes the invisible: rows are made of ticks 
Nothing that mysterious: it’s like the frames of a movie. Movies appear to out eyes like continuos, but they are a serie of about 30 frames per seconds.
Ticks are for trackers what frames are for video monitors.
the so-called “speed” parameter lets you change the number of ticks per line. This value is 6 by the fault, but can be changed from 0 (stop) to 1F (31 decimal), by using F1xx (F100, … F11F).
The y parameter for the 0Exy command represents how many ticks should pass until the sound should be retrigged (i.e.: the note should be played again).
y can vary from 0 to F, but cannot be higher than speed.
An example: suppose you are at F10C (12 ticks per line).
You can set 0Exy with 00<=y<=0B.
For example, set it to 4.
12 / 4 = 3 => your sample will be retrigger each 4 ticks, for three times, at tick 00, at tick 04, at tick 08.
Set it to 6.
12 / 6 = 2 => your sample will be retriggered each 6 ticks, for two times, at tick 00, at tick 06.
Set it to 9.
your sample will be retriggered each 9 ticks, for two times, at tick 00, at tick 09.
now, the x.
You can set the volume of the retriggered notes:
For example, if x = 7 (*1/2), each retriggered note will have its volume halved in respect of the previous.
the parameter x won’t work with VST instruments
So, a final example:
F10A (10 tick per line)
play the note C-3 at volume 30, with command 0E72
|ticks…note…volume
|00…C-3…30
|01
|02…C-3…18(30h/2=18h)
|03
|04…C-3…0C
|05
|06…C-3…06
|07
|08…C-3…03
|09
all of this occurs in a single pattern line.
See my demosong “The Path” for some examples about 0Exy usage.
welcome to advanced tracking 