I think that you cant remove your account from PTC to Google. I never saw that option do I think it's impossible. For IV I use aplication called GoIV. I didnt used IVstats but I think thats similar to this and it dont require your acount access. This application use your screen to read CP and HP and calculate IV.
GamePress
Pokemon Go support app for PTC users
A relative of mine chose to use a PTC account rather than a Google account when she began playing Pokemon Go some time ago.
With a PTC account, the only way to use an app like IVStats is to enter the PTC account login details, which seems risky (in comparison, with a Google account one can use an authentication key).
1) Is there any way to change the setup of a PoGo account from PTC to Google?
2) If not, is there any Android app similar to IVStats that doesn't require account access (e.g., the app uses screenshots rather than accessing the account)?
