As we know there are different DNA groups
One of the reasons may be that people changed their surname after the name of property they lived on or purchased
A good example in newer times I found in a newpaper article
This is an ancestor from the Dean Dirleton and Craigentinnie branch DNA is unknown but he is probably one of the NN that changed his name most.
1877 The DEATH of the Right Hon R A DUNDAS CHRISTOPHER NISBET HAMILTON, of BLOXHOLME, LINCOLNSHIRE, and of HALF A DOZEN PLACES IN SCOTLAND, is worthy of note, at all events on one account, as being the MAN WHO REJOINED IN THE LARGEST NUMBER OF NAMES. He began life as Mr. DUNDAS; then he took the name of CHRISTOPHER instead, on INHERITING a fine PROPERTY in LINCOLNSHIRE; then became SUCCESSIVELY Mr. NISBET, and Mr. HAMILTON NISBET on accession to two properties in Scotland, the one in Haddingtonshire, and the other in the country. He has left an only child, a daughter, whom it is said he would never allow to marry unless she would captivate a Duke, marquis, or an Earl at the lowest. I suppose that now he is gone, the embargo will be taken off and that MISS ISABELLA, DUNDAS CHRISTOPHER NISBET HAMILTON NISBET will speedily marry some untitled gentleman, the choice of her own heart-Nenagh Guardian Saturday, June 23, 1877 -Ireland