I think you might be right. They were related in some way but they weren't to close. I have a faded copy of Richard Hartles MD Hartle heritage vol 1 no 2. Here he describes the primary Hartle (Hertel) immigrants.
Adam Hertel 1709, Palatinate Hans George Hertel 1749, Baden Peter Hertel, 1771? Anna Marie hartl 1848 Bohemia William Hartle 1872 England
In Richards paper he writes: At first it was thought that John and Adam in New York were the grandsons of 1709 emmigrant Adam Hertel, however further research showed that his grandsons, John and Adam Hartle werwe residing in Cornwall township, Ontario Canada