NTP force system time in the past

Hello

I have a question that may sound stupid after and maybe it is.

We are syncing our sytem time via ntp from a reference time server. all works quite well
but due to a mall applikation which not accepts timestamps from our servers that in the future,
and if it even was 1 ms, we have to adjust our system clock to be 100 - 200 milliseconds behind the reference system.

I could not find any parameters that would provide such a functionality.

Any Ideas ?

You probably would rather fix you "mall applikation", whatever that be.