I ran into this same problem.  Reread the original bug report, ignoring the rest.  The poster respectfully made a simple query as to expected behavior.  From rasmus first response the poster was treated flippantly and with disregard.  And the poster didn't wilt, but instead answered toe to toe.
Anyway, now I have this code where user's skip answering fields (damn users!) and my code used to fill in the zeroes (or commas in the thousands).  But now my code no worky.  Will that cast to float work?  I was doing this elaborate if($in==""){0:number_format($in);} or whatever, but do I only have to cast to float?