You are correct. The dna testing has already shown that all the groups except one DID have a former surname due fact Spencer meant a dispenser of goods and services, so if a guy, say, was a blacksmith, named John Smith, but changed careers to have,say, a General Store, and he found-out the meaning of the new(ish) word, "Spencer" to the English lexicon, he then thought, "Hmm, that word describes what I do, now, so I'm going to change my last name to that now,as I'm no longer a blacksmith". And this went on all over England, as, say, a Mr.Green, no longer living near the Village green, now was a Sutler, providing "goods and services" to the army, selling provisions, also changed his name to that of Spencer. Same for many of the pursers/stewards, even for minor Lords, so one ends-up with hundreds of new "Spencer" families, who formerly were Coopers,Greens,Stewards,Smiths,etc.etc. Only one group was not told they had a former surname, as they originated it. So yes I am aware of the dna potential and that would be a key way to clarify who is blood related to my Spencer group and who is not, and in fact was one of the things I would event-ally recommend to someone who might contact me, so thanks for your suggestion.
And yes I do realize the percentages of each group of Spencers would change according to how many people participate, but it's also interesting that the percentages have held steady even as the number of participants
kept increasing. It's too bad if England has an outlook against dna testing, as it is a wonderful tool that can resolve many issues, including to whom one belongs blood-wise, as well as link one to others who often have papers that assist in extending one's lines back further in time. Well, we shall see what time and study brings to all of us. Thanks for the thoughtful words. Take Care, Vienna