I am reluctant to force the use of TP line as it is not necessary for position size calculation. You can add a TP line and save those settings to a file or to a template.
I can modify the PSC-Trader script to remove the lines when the trade is executed, but I am not sure that's a good behavior for a script to tinker with indicators. The next version of Position Size Calculator will feature a button that will show/hide the lines in one click, so that's no longer be a problem at all.
Thanks for your ideas! I will look if I can incorporate something from it in the upcoming panel version of the indicator.