These are the Science origin contacts according to the Homecoming Wiki:
https://homecoming.wiki/wiki/SERAPH
As you can see, there are multiple contacts in each level band until you start getting to higher levels. These contacts all share the same mission pool. When Jonathan St. John Smythe referred you to someone other than Samuel, was it one of the folks on this list?
Additionally, origin type contacts will offer to introduce you to contacts for other origins if you are in their level band. Generally, it is only after you progress into the next level band that they will introduce you to the next one in the chain. For example, if you complete all of Samuel Pierce's missions, but you are only L8, he won't introduce you to Jill Pastor. He will introduce you to contacts for the other origins as appropriate for your level instead. Once you hit L10, he'll introduce you to Jill or another contact on the SERAPH list from the next level band.