Solo travel on 4-day flexi pass 2-for-1

Hello,

My wife and I are visiting Switzerland in October. We are planning to get the 4-day Swiss Flexi Pass 2-for-1 deal. But we only have 3 pleasure travel days planned. I have work for the rest of our stay there. Can my wife use the Flexi Pass for solo travel for the 4th day? She would also take my Flexi Pass on her solo day with the date filled in, so she would have both flexi passes but would be traveling alone. I think this meets the spirit of the flexi pass holders traveling together - in this case the passes travel together :-) Is this allowed?

Regards,
Gowri