As I understand it the pay roll goes to the banks on the 14th of the month ie March pay will be under the current system. The 20th was deliberatly chosen for going live to give what remains of Admin branch a chance to correct the errors in the database before the pay run goes out on 14th April.
No I'm not a paid up supporter of Admin branch, it was just the only bit of the brief I listened to before falling asleep!
Give it a chance - the baseline software (Oracle?) is used by many big companies out in the real world (BA included I believe!) and you don't see many gripes from them. True, the military have adapted it slightly to take into account the "oddities" of military lifestyle ...
At the end of the day if you have control over your day to day life regarding pay / allowances / leave etc it has to be a good thing. The majority of posters here on pprune bleat about handbrake house - from March 20th (hopefully!) the only person to blame if your allowances are fecked up will be yourself.
And a 5% odds of having to provide evidence of a claim are far better than the current 100% evidence (as a certain Capt RN knows to his cost!).