[BUG] i3 Mega S E0 thermistor calibration preset incorrect

[hooskworks]

Bug Description

The extruder thermistor defined in Configuration.h for the i3 Mega S appears to be incorrect. Anycubic's Marlin build (from their github repository uses
#define TEMP_SENSOR_0 5

whereas this firmware seems to use 1 because of

#if ENABLED(KNUTWURST_4MAXP2) #define TEMP_SENSOR_0 11 #else #define TEMP_SENSOR_0 1 #endif

i can't see anywhere which uses the KNUTWURST_MEGA_S define to do anything else.

Correspondingly, after have fitted an e3d v6 hot end with a Semitec 104NT thermistor which should also be covered by option 5 i get an almost 50C offset in reported temperature and measured when using a k-type thermocouple attached to the heater cartridge. The delta is larger if i sample the thermistor cartridge or heater block.

Steps to Reproduce

No real steps to report. This is as a result of installing v1.5.4 DGUS TMC BLT onto an i3 Mega S with TMC2208 drivers, a real BLTouch, and e3d v6 hot end. Both print bed and hot end show a large variance from the reported value however only the hot end seems to have a firmware build related reason.

Expected behavior:
hotend reports closer (within 20C) to the temperature measured at the hotend thermistor by a separate k-type thermocouple

Actual behavior:
The reported and measured temperature deviate by as much as 50C at a set point of 200C after the hotend has settled and been allowed to reach thermal equilibrium for greater than 15 minutes.

Additional Information

This is a v0.0.2 mainboard still using the stock hotend harness and interface PCBs in the tool head and the base of the printer. The BLT touch has been fitted by running separate wiring from hotend to the main board and not using spare ways in the hot end harness.

Anycubic I3 Mega repository