You do know about "settrainerflag" and "checktrainerflag" and "cleartrainerflag" don't you?
And to sum up what the tutorial means:
You CAN use more than one type of script command (like applymovement and msgbox, for example) in the same script.
Although, you kind of got off from combining things, to trainerbattles only. O_o
I did learn something about trainer scripts though. I wondered what double battle type's number was.