From what you have given, it appears that the accrual period is calendar month.
In that case,
1)in V_T559L -
1.1)Selection rules - tab accrual period, select Month.
1.2)Quota types - for the quota type use unit = days
1.3)Base Entitlement -
Entitlement - 2 (days)
Related to period - select accrual period
If it is required, you may have more than one seq.no. - for example seq 1 for seniority upto 10 years, 2 for 10-99 yrs; or similarly based on age.
1.4)Also for seniority or age calculations, in V_T559L - Selection rules - tab Base entl: it requires a calculation process, key date for determining seniority; similarly key date for determining age.