Hi,
1) From which month are you changing the projection method? Payslip you attached were belonging to which payroll period?
2) For conveyance, it looks like the amount difference is less compared to HRA annual exemption between both projection methods. You can try to convince your client for conveyance to follow as system gives. But HRA exemption looks huge in value. You may have to analyse your payroll run (function INHRA) that why this variation happens.
As Bhabagrahi said, if there are any known implications in following SLPRJ as 1, then you can follow as per his advise.
But, is it happening only for mid-month joiners or for all the employees? How you are paying HRA and what tax code you assigned and how the exemption is calculated in your payroll log?
You can completely override /4E4 wage type in PCR by your own calculation and add it after INHRA function line in your schema. But again the issue is, how the exemption is calculated in sub-sequent month payrolls. It will be more confusing, when you use your own calculations by avoiding standard SAP functions.
What was the objective in taking SLPRJ as nominal by your client? What our previous company was doing is, use SLPRJ as actual (0) and adjust the income tax with voluntary tax for first few months.
As Venkatesh said, you can go through the pcr INWT and analyse, how it works (by calculating /12N wage type in par with /124).
regards,
Bala.