Well for the people that has similar problems.  the harmony support team has set my time delays to 90 seconds after I requested.  However, it did not resolve the problem as still my HUMAX receiver was not able to make its mind on what is the right time delay for a power on.  To be honest 90 seconds is a lot of time.  I am happy that support guys siad 300 will be too much and enlightned me..

I only wish that harmony provides us an interface (say an advanced settings tab) for each activity by whihc we could control each signal and time delays between each signal.  (being able to add, remove, specific key signals to activity with any time delay in between). Currently we are limited to a specific set of templates and I am sure I can do much more with the remote if such control is given.