You may be pretty confident, but the instructor is the one signing you off and you need a sign-off from and a bad one might stretch it out a bit, not be confident in their abilities and pass rate and might want to be extra careful or just overly protective of their pass-rate. It's tough to tell in your position and I think most instructors might err on the side of an extra lesson or two to make sure, but I only have my instructor ratings and never signed anyone off for a checkride. I have heard of bad instructors who knew a student had money and really, really milked it as they needed flight time and money and it horrified me, but I wasn't a witness to it I just heard the amount of flight time they'd had and where they were in their training and how upset they were.This has been a year long saga, I have a tough schedule with work. I’m trying to get this PPL knocked out and decide how I’m gonna finish the rest of it. So that’s the reason for multiple instructors. I feel pretty confident with my flying though.
If you got along with the other instructor that left for another flight school it might actually be cheaper to fly at a school that charges more if their instructors are better as you'll need less time flying with them in the plane. Which area of the country are you in? Perhaps some folks here have some ideas or suggestions.