It goes back to zero but that doesn't mean it stays there. This was one of the question we had about how the whole per month thing would be calculated. They decided to put it into accounts receivable which is fine but means all monthly revenue may not necessarily be broken down.
Like $15,000 for three years of service would be 15k/36= 416.67/month.
The way we are reporting it is that we get 15k one quarter but no revenues off that sale for the rest of the three years.