T-pace is your average 100 yard/meter time received from your 1000 meter time trial earlier in the program.
The 200 and 800 test is meant for you to compare results and see if you have a big drop off in pacing from the two tests. If so, this could suggest that you are powering through the 200 (ie work on form is crucial) and/or there remains a lack of endurance (ie work on endurance is still needed). Likely it’s a combination of both (plus add in executing good pacing). It’s a process!