That is one of the easiest to come up with replies and you see it all the time. Just because there are 5 gaps of 2 days with no signups you can call it "the usual". Not saying you shave, it's just going to be hard to pass that off on anyone. I have never pushed your program so I have no idea.
However, I have had steady traffic to my sponsor for 2 years. My ratios are in the bag. I can tell from hits within a couple hundred bucks what I will make that week, day, month, etc. Traffic is very predictable. If he has slumps of 2 days with no signups in a row no less, and the figures don't look right overall I would worry.
Why does everyone think traffic from the same source is not predictable. I would bet he knows his traffic better than anyone. Like I said, you could tell me how many hits I would have this week and I could guess almost to the exact amount of my check. The only time this drops is when my sponsors site gets fried, etc. Even if the ratio drops over time it is a steady slow drop. Not gone in 60 seconds.
PEACE