The original Vixen Star Book controllers allow the user to use multi star alignment to compensate for errors in polar alignment.
The alignment process will actually compensate for very rough polar alignment provided a good number (20+ stars or objects) are used to align the scope and mount. However, the compensation in the software algorithm may then cause "jumps" in the mount tracking which are especially noticeable (and unwanted) when using the scope for imaging.
To avoid this, when imaging only use the polar alignment scope for initial polar alignment. The Star Book does not retain alignment data when powered off so the "memory" will be cleared when powering on. Following the manual polar alignment using the scope, a drift alignment or other alignment correction procedure can be used to fine tune the position of the mount.
The backlash compensation adjustment can then be used in conjunction with the autoguiding function of the mount.