I have five Asher ELYs indexed in my database, though none born as early as 1768:http://dgmweb.net/FGS/Indices/EveryNameIndex-Ely.html
As far as I know, the Asher ELY's are all descended from an English immigrant, while I descend from a German IHLE/ELY immigrant, so none of these would be "my" 4th great-grandfather.
I work on all ELYs because I'm the admin of the ELY Y-DNA Surname Project:http://dgmweb.net/DNA/Ely/ElyDNA.html
And for the same reason, I stop following an ELY line when it daughters out, so I would not in any case have your line beyond Asher's daughter, Sarah.
When researching, don't forget to take into account that new counties were being added in Pennsylvania up through 1878, so a change in county name may not represent a move on the part of the family, but the spliting off of a new county. For example, Carbon Co. and Lehigh Co. were formed from Northampton Co., which was formed from Bucks Co.
You may find this page at my web site helpful in that regard:http://dgmweb.net/Ancillary/Geog/PA/PA-Cos.html