I have no further information on this accuracy business. If you can find a 'buddy' who has studied or is studding the subject it might be helpful to work through a few exercises together it might help.

Regarding accuracy, there are two considerations to keep in mind -

(a) for the exam, provide the examiner with whatever level of accuracy he desires .. ie fly the check captain. Bob is well-placed to comment on this consideration.

(b) in the real world, there exist numerous minor errors in all these calculations and, indeed, the empty weight data and certification data. There is absolutely no point achieved in running sums to ridiculous precision .. a bit like measuring the distance between Melbourne and Sydney using a metre rule stepped along the road when a car odometer will provide a sensibly usable figure.