727 2-3 upshift VERY harsh

Just guessing but when people have their transmission rebuilt at transmission shop the shop more than likely have to do some fine tuning. So you are fine tuning it now. I would recommend getting a torque wrench and doing to the proper torque before you back off of the adjusting bolt. Then you will know for sure where you are at on the adjustment. I would still call them and bother them until the issue was resolved. It might be internal.