This is the explanation provided on findagrave.com:
"After Theophilus Simonton I died in 1754 in Lancaster PA and was buried on his land in PA, Mary his wife, and his son William, his youngest son and the "grandchildren" came to Rowan Co. NC. Also believed that Daughter Mary who married Samuel Thornton in Lancaster Co. PA and Patrick Duffey came with them at this time. Patrick Duffey was a person who the Senior Theophilus Simonton brought over from Ireland as he was a close friend of his family Or possibly a brother in Law and so he worked for The Senior Theophilus in PA.
'Shortly after son William came to Rowan Co, he married Mary McKee.
Mary, Theophilus Simonton's wife died in Rowan Co and she is buried in Statesville (Rowan) Iredell Co.
"Theophilus Simonton's will was probated in Rowan Co but he died and he was buried in Lancaster Co PA. He is buried on the land he so loved in a private Cemetery. Today there is a very small stand of trees in the middle of a beautifully tilled field just below where he lived.:
Also one daughter, Ann who married Andrew Allison died in Lancaster, PA. and is probably buried with her father as is her brother Theophilus II and wife. Ann's husband and children went to Rowan Co. PA. after Andrew Remarried in PA.
"Theophilus signed his own will in a very shakey hand and it was spelled "Theophilus Simontoun""[[http://www.findagrave.com/cgi-bin/fg.cgi?page=gr&GRid=94635232]]
Obviously, a descendant carried the will from Pennsylvania to North Carolina where he settled and thereupon had the will probated in North Carolina rather than in Pennsylvania where the family had previously lived.
For other oddities of this will situation, see [[http://wc.rootsweb.ancestry.com/cgi-bin/igm.cgi?op=GET&db=jkh1s&id=I12290 ]].
Sometimes, it's the spirit of the law that gets better served than the letter of the law. With the descendants all in North Carolina, they obviously didn't want to return to Pennsylvania for an extended period of time to get the will probated there. There were apparently two Theophilus Simontons in Pennsylvania around the same time and an empty will packet dated 1750 was also found in Pennsylvania and it didn't belong to the Theophilus Simonton who wrote his will in 1754.