Weird sleep patterns affecting REM cycles?

I have to admit, my sleep patterns are pretty messed up.
I have always had trouble falling asleep and getting up, it just feels like the day is too short, I'm not tired when I go to bed, and I feel exhausted when I wake up.
Combine this with me studying at night and sometimes having to go to school in the early morning, you should be able to guess how random my sleep patterns are.

My question is, how does this affect REM cycles?

I'm asking because I've had mixed success with the WILD technique using WBTB.

In my first few wild attempts, which I always performed after 6 hours of sleep, I had a very hard time transitioning into a dream.

However yesterday, after just 2 hours of sleep (I woke up in the night), I figured I'd attempt a WILD for a few minutes, would take me some time to fall back asleep anyways.
I got into SP quickly as usual, kept a clear mind, started seeing the usual plasma clouds moving about, and then got this feeling of a scene.
This always happens when I try to WILD, usually those scenes disappear after a second or so, but this time it didn't.
I started to wonder if it was a dream scene, so I decided to try to focus on it.
Faint images of the scene appeared so I went for it and thought "This is a dream! Let me in! DREAM!" with all my power.
Funnily enough, I immediately transitioned into the dream... smoothest WILD transition I ever experienced (usually I'm catapulted into dream scenes at high speed or fall from the sky).

Is it possible that due to the weird sleep patterns, I may not be in an REM phase after 6 hours of sleep, and I'm having a hard time transitioning because of that?
Or are WILD transitions random like that, very hard one day and a piece of cake the next?

Cheery,
Hyu