Hi,
I hope you referring variation due to loss of pay or new joiner joined in the middle of month.
Obviously based on the number of days worked variation will be there in the earned Gross.
For better understanding you can have 3 column in the payslip like
1) Fixed Gross with break-up ( which will not change unless other wise there is pay revision on year basis)
2) Earned Gross ( based on the number of days worked for the month) which will vary from fixed Gross incase of loss of pay / Employee joined in the middle of pay cycle. Accordingly all components will vary right Basic/HRA / Conveyance / other Allowances.
3) Deduction column : Statutory deductions like PF/ESI/PT/Income Tax will reflect here.
Net salary will be the amount which will be arrived after deducting the total deduction amount from the Earned Gross.