As mentioned by Sujith and Sally, constants in V_T511K often need to be defined from the beginning of time until the end of time so that the system can read it's value no matter when.
In a Payroll PCR, you could go by with having a constant that exists only from 01.05.2013 to 31.12.9999 only if the PCR itself would be delimited by operation CMPER 1305 and that the constant would exist only for the return value = or >. In such a scenario, retroactively processing period 04 of 2013 would not call the constant.