Hello, I also have a below 300 OAT score and I have scheduled to retake in January. I too, was contemplating on whether I should turn in my app now, or wait until my retake. After emailing a few schools, they told me to turn in my application anyways and MARK on OptomCAS and write in the supplementary essays that I am planning to retake.
So I did just that, and do you know what happened? I applied to four schools: PUCO, PCO, MCPHS, and Western.
I have received interviews to PUCO, PCO, MCPHS, and still waiting to hear back from Western.
PUCO is my #1 choice and they have expressed that they still want me to retake the OAT, but I guess they were impressed with my overall application.... so they invited me for an interview (I'm so grateful).
In conclusion, it definitely wouldn't hurt to turn in your application now. Just make it clear on your application that you are planning to retake the OAT. Who knows, you may get a few interviews before your retake. It takes a couple of weeks for OptomCAS to process your application and send it out and another several weeks for the schools to review your application, so the quicker you send in your app, the better.
Hope this helps, you can PM me if you want to know any of my stats.