Return a borrowed ProE/Creo license?

Hello all,

Anyone know if it is possible to return a borrowed proe/creo license?

I've seen the message in the proe_borrow.bat UI (attached) which says that you cannot.  Is this really the case?  Seems ridiculous, it's not hard to imagine this being seriously detrimental. 

Have tried using ptcflush.bat, it gives the message (paraphrasing) 'cannot return a linger license'.

Using creo\elements 5.0 M150

Thanks!