Yup exactly, if I'm on emergency calls, I get payed 10% of my base hourly to be available, online in 15minutes and ready to solve issues. As soon as I get a call during this time, it's overtime (125% of hourly pay, bonuses for weekend/night calls). If I'm on holiday I'm out for the company, but I'm there for colleagues. With this system did daily rotations and weekly rotations, both lengths have their pros and cons.