Basic Pay split

Hi Experts

I have a scenario which is explained below

XYZ employee basic salary( wagetype let say 9BAS) as follows

01 Jan 2018 till 12 Jan 2018 -10000

13 jan2018 till 31.12.9999 -20000

I f there is a split then the latest amount should be read i.e 20000. Can you please guide me how to achieve this through pcr and if through a pcr where to place the pcr in schema

Best Regards

Manu