Yes, I meant high and low volume.
Well, they would first calculate the volume in terms of the number of lifts. Then they would (relatively evenly) distribute the weight throughout the training year. For the prep. period they would do lower intensity, but they still had a minimum number of 90-100 percent lifts they performed, whereas in the comp. phase they performed more high intensity lifts, more lifts in the competition exercises, and less low intensity stuff.
Strictly speaking they didn't "alternate" high and low volume days. If h=high, m=med, l=low, then they may do weeks like this:
4 training days per week:
The point is that they distributed the loading to give the athlete variety (by switching the volume) and recovery (by now having too many high volume days in a row). It gets MUCH more technical than this, because they have recommendations about the volume of eah lift in terms of the total loading (i.e. classic snatch lifts were about 5% of the TOTAL loading of their athletes under Medvedev, while special snatch exercises made a greater percent (pulls, sn. squats, ect.)).
They also have recommendations about how many lifts in each exercise should be in each zone of intensity (60-70,70-80,80-90,90-100,100 plus), how to plan the workouts (a lot is common sense, like don't do high intensity lifts at the end of a workout), and which exercises to include in a particular stage of training for a particular class of weightlifter. Higher class athletes use more exercises in their training (similar to Westside).
Now, James' method is of alternating intensity, not volume, and I think your interpretation is essentially correct. If you want an upper/lower body split then you've basically walked into Westside, because that's how they train (DE one day, ME the next). For total body days you'll have to get a little more technical because you'll be working a lot more muscle. What you do will depend on your goals, in the end.