A curiosity - from where are the "Achivement Points" gained?

I have met 113/120 achievements, and I have 2720 achievement points.

Meanwhile, a friend of mine has 107/120 achievements, but 2790 achievement points. Less achievements, more points.

We both have met the same number of puzzle pieces, monsters, etc.

All of that is to say that I don't think achievement points come from achievements. So, what is the significants of "Achievement Points?"

I knew it was something other than the achievements - but, here's my deal.

I've done maxed out first every single time, and am at max level. I'm just trying to figure out how my friend has more achievement points, when by all figures, she should be behind - she missed out on a couple of "maxed out first"s.

Not a biggie, just a curiosity.

if you do the slider puzzle every possible 20 hours but someone else does it once a day then you can easily have hundreds more points. there also may be other repeatable quests/achievements that I can't think of. but just think, just 10 puzzles is 100 achievement points, I'm several hundreds behind due to my 3.5 month hospitalization.