Difference between 30min PDC and 30min FS power

Hi,any xert runners here?
I can see that my 30min power on fitness signature (175w) and 30min power on xert PDC (180w) is different. Why is that?
I’m planning to do a 5k run race this December and my previous 5k run was around 31min with average of 173w. I’m planning to use the TTE datafield on my garmin watch during the race. Which watts will the datafield use?
Below are some pictures for reference.