737NG Moving throttle handles using Stepper motors

[olealm]

Started planning 737NG Autothrottle.

Have a few questions, hoping a kind gentleman with experience could give me answers..

- Stepper motors.. As I understand it there is no feedback from the motor itself, like there are from servos. Movement is based on pulses given from a controller moving the motor a certain amount of steps clockwise or counter-clockwise. "Calibration" is based on the controller "counting" number of pulses given (+/-) thus calculating the position. So far so good, but what happens when A/T is off and the handles are moved manually. Invoking any speedmode or TOGA thereafter - wouldnt the controller then have lost its knowledge of the current position??

- Anyone successfully used Steppermotors and FSBUS to implement moving throttles? Program example for FSBUS Router?

- Is there ONE FSUIPC Offset (for MCP or CDU auto-throttle setting) that can be used as input for controlling the throttle levers? Or are there many offsets depending on which mode is active?