I'm kind of in the same boat. I didn't really expect to receive interviews with my current scores, but I have. The thing is, like you, I'm already kind of invested, but I haven't paid for it/signed up for a date yet. I didn't indicate on my aadsas that I was retaking nor did I tell schools that I was retaking because I was so unsure for so long. The reason I've been holding back against signing up is because the majority of schools are starting to review now and will send out more interview invites mid-late augustish, so I was hoping to just see what happens with my current scores but still studying for it at the same time. I would say that retake it as long as you're confident that you know the material and know you can do better. I'm not sure if schools can rescind their interview invitations, so I guess that's something you'll have to contact schools about individually.