BTW, I just realized another way I use multiple licences: filing multiple flight plans (e.g. outbound flight plan and return flight plan).  [See this thread: https://www.iflygps.com/Support/Forum...ope/posts#36694] 
iFly currently limits you to one filed flight plan per software copy.  But there's no problem filing a flight plan on my home PC and then immediately filing the return flight plan on my phone or tablet.