Retrieving Coinciding date with Sequence Number

I have a table that contains a sequence number for every calendar work day and the matching calendar date. I am linking a table that has a start date that I need to work with. I want to add a cycle time number to the sequence number for the given start date. I then want the report to show the calendar date that matches the new sequence number.

I know this is very confusing, I am attaching an image that shows the fields which may make it a little easier to understand. Any help would be greatly appreciated.

Thanks,
Babs827Why does the second sequence number is 270?