What you are reffereing you must be without bands. I have their band training manual in front of me as we speak. It waves from 47-53%. I also have their poster on my wall which has the cycles without bands and the wave is from 50-60 for beginners, 60-65 for intermediate, and 55-60 for advanced. The bands they recommend you using based on squat max is ..
30-500 Light Band (Purple)
500-750 Average Band (Green)
750+ Strong Band (Blue)
Bench press is a bit different. Weight stays constant anywhere from 40-60% during the cycle. It is not waved. The more advanced the trainee the lighter it is. With bench press if chains are being used the weight is the same as the percent. However if bands are being used you subtract 30 pounds off of the %. Westside only uses mini bands for bench. Metal Militia is another story.