I´m going ahead with programming my own project. I used some of the OSCAT blocks. While simulation it turns out that those Blocks using your T_PLC_MS are running much to fast. My first thought was, that there might be something wrong with your T_PLC_XX function. I apologize for that! Everything fine with them. Taking a closer look to the problem I found out, that XX_TO_TIME are not IEC compliant. At the end it is the DINT_TO_TIME which I suspect to be wrong: It is using seconds instead of millisecs. Dividing the T_PLC_XX output by 1000 seems not to be the best option because of the resulting minimum resolution of 1 sec.
Do you have any chance to fix it?