Hi,
Tania is correct. You should be cautious on using SLPRJ as 1. This configuration not only affect conveyance exemption but also for the entire tax calculation, company-wide.
Your system may show less exemption only in April month and afterwards, it may change, as he earns more salary (for full month). Was it true in your system?
(Means, in April it show 4800 and subsequently it may project more and show more exemption value?)
If above is the case, then you may adjust with voluntary tax and try to deduct less tax in April.
regards,
Bala.