It probably doesn't matter that much but Dr. John Kittredge was b. Billerica in 1666.  He died Billerica, not Tewksbury because of timing.  Tewksbury was formed from part of Billerica in 1734, he could therefore not have died in Tewksbury.  The death record is in both Billerica and Tewksbury records.  The planning of making Tewksbury a town was probably well underway by the time of his death. So it's probably a difference without a distinction.  I suppose some might change their trees based on this fact but most will find it irrelevent like I do.