Is The Following Appraisal Letter Correct?

Hello,
I have been a given a hike in salary effective from April 1st 2013.Subject to appraisal conducted for Calender year 2012 right? The hike letter >>
Dear XXX,
We are pleased to inform you that the management has taken decision to revise your salary in recognition of your performance effective from April 1st 2013 subject to the appraisal conducted for the calender year 2012.
....

Dear Krishna
What is the appraisal cycle? Is it Calender Year or Financial Year. If the same is calender year then the appraisal and salary hike may be with effect from 01 Jan 2013.
With the above sentence you can mention the employee's existing Cadre/Pay scale and revised Cadre/Pay scale.
In future also, it will not be revised automatically and it will be made only based on employees' future performance. The revised pay scale will be given for one year period only. The PF/ESI and other superannuation benefits will get attracted only on Basic and DA and not on other allowances.

Well, it depends on the company's appraisal policy. Some companies do appraisals on the calender year basis, some on financial year basis and some on the tenure (when an employee complete an year or 6 months with company) basis.
In the above it looks company doing it on financial year basis but the appraisal letter should also include details about payroll/payscale infor with along with previous salary amount, increment amount and the revised salary amount...

Dear Mkkrisna,
Congratulations for the pay raise! I know you deserved it. Find out what is your company's appraisal guidelines, there should be some basis or rulings for the purpose. Every company have different guidelines and employees should know and employers should state the rulings.
With regards,
NBAton
TNSPI, Philippines