Sure sounds like a symptom of OCD. A pathological compulsion for something you cannot necessarily explain or validate. However it's more complicated than that, as a comorbid symptom of autism. I know personally symmetry and physical order of things of any kind tends to be an obsession for me. Though I often try my best to hide such symptoms if I can. Whether I must carry at least four of each coins in my pocket if possible. Or make sure the lock on my front door is secure- no less than four times each night before I go to bed. Sound familiar?
To my knowledge OCD doesn't just "tag along" with autism. I know in my own case my doctor explained my OCD as the result of personal traumas that befell me in the same year. It's like a form of PTSD that lingers in your life.
As someone with diagnosed OCD, I can only suggest you pursue it further with your therapist or doctor. Find out if you really have it, and more importantly what may be its root cause.
BTW- I cut my shoelaces if I have to, just to make them the exact same length and tightness. Why do I do it?
-BECAUSE!!!!!!!! (No rational explanation required with OCD. It's an obsession you are compelled to do.)