As far as the loading the DTC and the MFD’s, it’s sounds like you haven’t programmed MFD preferences for the DTC and it’s loading a default or an ‘attempt’ (whether intended or unintended) to change them on the DTC. Doesn’t matter which MFD you use to load the DTC; the DTC contains info your preferred MFD setup …. obviating the need for programming them in the pit.