Heroku R14 workstation error (memory quota exceeded)

I am running Unicorn + Delayed_job on Herkou. I am getting R14 memory quota exceeding errors when I am apparently using only 246 MB out of the 512 MB allowed (1X worker). Here is a screenshot of my new relic. I'm not sure how to set the number of instances for the working background to work. I don't think WEB_CONCURRENCY

unicorn.rb controls this, but I could be wrong. Any ideas?