The document will share the SAP standard behavior to display wage type text in T-code pc_payresult.
Every employee will have certain Country Grouping (basing on Personnel Area has been assigned in Infotype 0001).
Opening table T500L (you can check by T-code SM30 or SM31) with corresponding Country Grouping (only 1 record in the table), you can find ISO code.
SAP will use the ISO code to retrieve text configured in table view V_512W_T.
In my current system, my employee has Country Grouping AE, and if I only maintain wage type text in table view V_512W_T with country grouping AE, the wage type text in pc_payresult is blank.
So in order to display wage type text in pc_payresult, you have to configure table view V_512W_T with corresponding ISO.