I recently spent several frustrating hours debugging a problem which had arisen on our home grown proxy server where requests were instantaneously timing out. The cause of the problem was that successive calls to SECO() in FP26DOS returned values which in some cases were smaller than previous ones. The differences were small (less than .05 seconds) but I just can't figure out how FoxPro apparently thinks that time runs backwards!
To prove to myself and my colleagues that I wasn't hallucinating I recreated a simple test program:

clear 
for j=1 to 100
   ts=seco()
   do while .t.
      mtimenow=seco()
      if mtimenow>ts+3
         *3 seconds - no response - time out
         mpsreturn='timeout'
         exit
      endif
      if mtimenow mpsreturn='SECO() time error'
         ? mpsreturn,ts,mtimenow
         exit
      endif
   enddo
endfor

The results show that the behaviour is consistent - at least on my machine and several others here.

Has anyone else experienced this?
BTW the fix in the end was simple (if not elegant): I introduced a half second wait between the first call to SECO() and the second - which is really weird because now to detect a time out I have to slow things down!!!