I used a Spark of Light on my level 10 titan. My expectation was that I would be granted 15 levels of experience, instead of getting a little bit of experience and being bumped up in number. I was in my non-leveled Defender subclass and gained only two skills. I found a YouTube video (linked) of someone starting with a level two and they had the same result. Seems kind of funny that you hit level 25 and only know two skills, no?