Nose wheel & MLG arms for wt & bal. calculations

Greetings,
The original spec specifies -16 and +44 for these stations respectively. However, after the dual nose fork and MLG spacers to reestablish level, my measurements have changed. Dropping a plum bob from the datum, I am measuring -17.5 and +42.5 respectively. Has anyone else found this to be true? Thank you. Scott