When you talk about Tempo PL 13.3 workout, I guess this is Hugin?
I am afraid high PL there is due known bug – sprints in otherwise steady workouts inflate PL grossly. Without those bursts, this workout would be around Tempo PL 7.5.
Anyway, this bug aside, you might have stumbled to another bug or hidden feature:
- other bug: AT suggestions are capped at PL 10. Suggesting higher can be bug or alternatively,
- hidden feature: with partially implemented new Workout Classifier, AT knows real PL and is able to suggest this as appropriate workout while UI still shows invalid PL.
One way or another, if you are concerned that inflated Tempo PL might affect your future workouts, you can contact with TR support for help to sort it out.