NMC - refund nurses retiring nurses and midwives for the part of the year not worked.

In a year's time, my husband, a staff nurse, will pay his NMC fees for 2017/18. However, he is due to retire in February 2018. As things stand at the moment, he would effectively be paying for 8 months that he won't be working and other nurses and midwives will be in the same boat.
I would like to see him pay the £120 in October 2017 but then, on retirement, be refunded the £80 for the months he won't be working.