Yes, I find I have to press really hard in order for the kiosk to report "Excellent" quality for all four fingertips. I hadn't thought of using my other hand to help press, but it's not a bad idea on a particularly stubborn machine.

They definitely should recalibrate the machines to allow for a second attempt. They also might slow down the time limit. I speed through the kiosk procedures because I've done them so many times, but newcomers might want to stop and read the text on each screen, and the counter might run out. I don't know why there is a time limit anyhow.