Birth month of May is disputed by some to be July assuming the document shown was based on the Gregorian calendar. It is very unlikely the record shown would indicate a birth and death based on different calendars, Gregorian/Julian. How would the average person then determine his true lifetime? Those in disagreement simply need to include any conversion they understand for their own family trees and apply as desired.
"The best policy when researching original records is to write the dates the way that you see them. Some Quaker researchers have transposed the dates into what they thought were the correct' dates. As you can imagine, these types of erroneous conversions could seriously affect the family stories. Misdating may lead you to erroneously conclude, for example, that a woman was pregnant prior to marriage or that the children were born after the family moved to a new meeting. To learn more about Quaker dates and calendars, order : Thee & Me: A Beginner's Guide to Early Quaker Records. Available on Amazon.com, available as an eBook or in printed format. The printed book has dozens of illustrations and images, including a bonus chapter with a case study demonstrating step-by-step how to perform a successful search using the Quaker Collections on Ancestry.com". https://www.ancestry.com/corporate/blog/quaker-calendars-dates-in-just-two-days-tomorrow-will-be-yesterday/

Son of Joseph and Elizabeth Miller
wife Mary Newlin 1739-1818-m. May 6 1757
Son Joseph married Elizabeth Newzum, d/o Richard
Sons, Nathaniel, Daniel, Isaac, Joseph

Burial source: from Marian Johnson
http://files.usgwarchives.net/pa/lancaster/cemeteries/sadsburyunmarked.txt

Regarding your information about Joseph Dickinson and Elizabeth Miller - Joseph
Dickinson was the son of Daniel Dickinson and Elizabeth Scott and was born in
Edenderry, Offaly, Ireland, Elizabeth Miller was the Daughter
of Gayen / Gawen Miller and Margaret Henderson who were also said to be from
Ireland. Gayen settled in Kennett Township, Chester County, PA as early as
1702, and his daughter Elizabeth was born in Kennett Township, NOT England.
Marian Johnson (#47442963)