Hey, I never post on this site, but I've been lurking a lot this week in anticipation of July 13th. I took my exam June 7th and I'm telling you - you can DEFINITELY pull up your score by a significant amount within a week...maybe 220+ would be a stretch, but definitely somewhere within the range of 215 or so.
I took my first NBME 12 two and a half weeks out and got a 218 (I was hoping for a 230). I was feeling discouraged and reading studentdoctor forums didn't help - so many horror stories of people regressing with their NBME scores. I ignored it, kept on chugging away everyday and decided not push back my test date - I'M SO GLAD I KEPT MY ORIGINAL DATE. A week later, I pulled up 10 points to a 228 on NBME 7, and by 3 days before the test I pulled up ANOTHER 10 points = 238 on NBME 11. So I managed to go from a 218 to a 238 in two weeks.
Looking back, I think I took my first NBME having barely finished FA. I just needed some more time to synthesize all the info I had gone over and make it click in my head. Once I got the big picture, my UWorld scores started going up, and my NBMEs followed suit.
It's really a matter of priority for you. If you think you won't be able to live with yourself with score under 220, then maybe you should consider pushing back your date. But if you would be okay getting something between 210 and 220, I really think you can pull it off in week.
Whatever you decide, keep chugging, you can do it, and GOOD LUCK!!!
- MS3 in NYC