If you look in the AP3392 under flying pay, it clearly states that:
b. NCA Commissioned as Pilot or WSO
(1). With effect from 1 Apr 03, NCA who began IOT on or before 31 Mar 03, will continue to receive their NCA rate of FP during IOT. On commissioning and during Pilot or WSO training, they will continue to receive their NCA rate of FP until such time as they have completed a 72 week QP, or are suspended from such training. They will then transfer to the Initial Rate of FP for officers and will remain at this rate for 4 years. However, time spent in receipt of NCA rates of FP is to be counted towards progression up the officer rates of FP.
(2). With effect from 1 Apr 03, NCA who begin IOT on or after 1 Apr 03 will continue to receive their NCA rate of FP during IOT. On commissioning and during Pilot or WSO training, they will continue to receive their NCA rate of FP until such time as they successfully complete Operational Conversion Unit (OCU) training or are suspended from training. Following successful completion of OCU training, they will transfer to the Initial Rate of FP for officers and will remain at this rate for 4 years. Time spent in receipt of NCA rates of FP is not counted towards progression up the officer rate of FP.
c. NCA Commissioned in the Same Aircrew Category.
(1). With effect from 1 Apr 03, NCA who began IOT on or before 31 Mar 03 will continue to receive their NCA rate of FP until the date of their commissioning, if commissioned in the same aircrew category. On appointment to commission, they will transfer from NCA rates of FP to equivalent commissioned rates of FP. NCA in receipt of the Initial Rate of NCA FP on commissioning will transfer to the Initial Rate of FP for officers and NCA in receipt of the Middle Rate of NCA FP will transfer to the Middle Rate of FP for officers. Time spent in receipt of NCA rates of FP is to be counted towards progression up the officer rates of FP.
(2). With effect from 1 Apr 03, NCA who began IOT on or after 1 Apr 03 will continue to receive their NCA rate of FP until the date of their commissioning, if commissioned in the same aircrew category. On appointment to commission, they will transfer from NCA rates of FP to the equivalent commissioned rates of FP. NCA in receipt of the Initial Rate of NCA FP on commissioning will transfer to the Initial Rate of FP for officers and NCA in receipt of the Middle Rate of NCA FP will transfer to the Middle Rate of FP of FP for officers. Following transfer to the officer rates of FP, they will remain at either the Initial or Middle Rate, as appropriate, for 4 years. Time spent in receipt of NCA rates of FP is not counted towards progression up the officers rates of FP.