Why does the Level 1 facilitator fee vary from year to year?

Based on the current fee structure Level 1 facilitators are required to pay $750 at the end of year 1, 3, 5 etc. and then pay $900 a the end of year 2, 4, 6 etc. as at the end of every 2nd year there is an online Refresher Course that must be completed that attracts a $150 fee.