On Tuesday, August 29, 2017 at 10:32:19 AM UTC-4, wrote:
in a 13 week quarter and a baseline of 62.7% what would be my weekly average needed to achieve a 2% shift?

What's the weekly average now? Divide it by 62.7, multiply that by 2.
That's how much you need to add or subtract to get to 64.7 or 60.7%.