Can we pass any dynamic value (which is the max value of another table column) in "Start at Value" in ADD Sequence step.
Please guide me.
Yes, but as the step is written you'll have to be sneaky about it.
Create two transforms and wrap them up in a job. In the first transform, query that database to get the value you want, then store it in a variable. Then in the second transform, which you should execute in the job after the first, in the Add Sequence step use variable substitution on the Start at Value field to sub in the value you previously extracted from the earlier transform.
Note that you can't do this all in one transform because there is no way to ensure that the variable will be set before the Add Sequence step (although it might seem like Wait steps would make this possible, I've tried it in the past and was unsuccessful and so had to go with the methods described above).