Interval training on the elliptical?

i do ten minutes jogging on treadmill then another 10 on elliptical then a 10 on the stepper----- but you can do 15 running 15 elliptical? because i hear that sticking to 1 thing isn't really beneficial. if you are on the ellllliptical use "cross training mode" - it works out your whole body! i lost alot of weight on elliptical too. its not a complete workout if i don't do some time on it.