Sounds to me like something went wrong with taking the reading.
Out of curiosity, I ran the numbers through my software (Brewtarget, 'cause I'm one of those crazy Linux people). 7.5 lbs of LME should only give you a gravity of about 1.054. Heck, 7.5lbs each of amber and dark LME only gives me a gravity of 1.108. I don't have the data for cocoa powder, but it seems unlikely that your hydrometer reading was correct. Might have been resting on the bottom, might have gotten stuck to the wall of your test cylinder, the paper might have shifted (check the gravity of water to rule this one out).