Yes, you can work on what you aren’t good at which may just be a focus duration you haven’t been training at. When you avoid something, you tend not to get better at it. 
Consider selecting a type from a different quadrant as shown here –
Ranking Spider Graph and signature diagnostics? - Support - Xert Community Forum (xertonline.com)
The new Challenge feature could be used to do this. Challenge yourself to get better at ____ for 30 days and measure the results. Same TL. Different focus.
Also consider what @rogowskiwo mentions. While his TP flattened his ability to repeat maximal performance at a duration improved. Suddenly a route that used to tax you isn’t so hard anymore. You reach a new level of fitness even if your signature numbers haven’t changed. However, course times may go down or you feel remarkably fresh afterwards.
See: Fitness – Power versus Repeatability – Xert (baronbiosys.com)