In the last match that we have data for, there were 30 US MD seniors who had better step 1 scores than you. Only 1 didn't match (probably had a real red flag). This is the only truly objective criteria that programs can use to compare you to others. If you applied to only the best 30 programs, I would think you'd have a decent chance. As long as you have ~15 programs that take ~1 DO/year, based on past years stats you should be fine if you really do interview ok. No harm except $ in adding more, but as everyone has said, most invites haven't gone out... Especially those from the competitive programs. Yes, the time to add would be now... But given that you applied to 30!!!, that your step 1 makes matching to psych a strong match chance on coitm (85+% for all Independents with your score, including fmgs), and for independents 10 ranks makes a psych match > 85%... But you're really above those stats since they are comprised largely of people trained outside the US.
Maybe I'm totally off base here... And there are always a few SDN super alarmists who will disagree... But most of the *best* applicants haven't heard from many places unless they live in and want to live in middle America (nothing wrong with that, just fewer applicants)...