I scored in the 70s for all of my practice exams as well and passed the PMP on the 1st try. Obviously, everyone is different and some folks feel more comfortable sitting for the exam once they achieve higher practice scores. However, don't let the scores in the 70s discourage you! Best of luck and looking forward to hearing about your success soon.
Training for Project Management Professional (PMP)®, PMI Agile Certified Practitioner (PMI-ACP)®, and Certified Associate in Project Management (CAPM)®