Guys in my class, or just prior (early 2011) had their upgrade interviews at the 3 1/2 year mark on the 330/340. One has just finished his line training. So almost exactly 4 years from his 1st EK line flight.
Guys who went 380 (forced or requested) from the same period are interviewing over the next 2 months. May and June.
Don't think it will be the same for new joiners now.