It is possible to achieve a precision of a few miliseconds, depending on your machine's speed.
I have just finished creating such a batch, and though I won't share with you the actual code, I'll give you some pointers:
Use %time% variable, and devide into substrings (without ":" and ".") - one substring will get the seconds, the other - minutes (you may add hours, for delays of over an hour, and even incorporate the date)
Use set /A to transform the time variables into 1 integer representing the amount of seconds which have passed since a rounded hour (X:00:00.00). Add the inputed delay (in seconds) to that.
Create a short loop, comparing the value of the combined var (explained in section 2) to the current time (need to recalc the curent combined min+sec value, inside this loop), and exiting the loop when the match is true.
One major bugfix here - you'll need to truncate any preceeding zeros to variables which are about to get evaluated in a "set /A" command. I've noticed that the console's evaluator (for this command) returns an error when an integer with a preceeding 08 or 09 (or simply 08 or 09) is used.
Remark:
This will only work with command extensions enabled. To test it, use the following at the beginning of the routine:
verify other 2>nul
setlocal enableextensions
if errorlevel 1 goto err
And then add an error handler subroutine named "err".
If you'd want to continue your batch in the same file, use "endlocal" after the looping subroutine.
BTW, this applies ONLY to Windows XP service pack 2 or 3.