How is this mastery?

I was having a discussion with a high school sophomore this week. She was talking about her latest summative science assessment. She had scored a 3.5 (don’t get me started on .5 grade deviations!) and was inquiring about whether or not she should retake the assessment. Knowing that the school is proficiency-based, I assumed (incorrectly) that any assessment could be retaken as many times as the student needed to show mastery.  Instead, I discovered that the student would receive the lower of the retake grades. She was shying away from seeking mastery, for fear of LOSING points!

I am curious as to how this is justifiable in a system that claims to value growth over achievement? Any student that has to consider whether or not to put extra study and effort into an assessment, for fear of losing points?

I have this discussion often with students. This practice does not seem to have a place in a proficiency-based system. I understand that students are preparing for college, and that colleges will require high stakes assessments. My belief is that high school should prepare students to study, to unlearn, relearn, correct misconceptions, and learn the executive functioning and transferable skills necessary to BE successful beyond high school. Is it me?