Hi and Welcome...
(To be said in the voice of Mr. Mackey from South Park...) True position failures are bad... mmm-kay...
Sorry, couldn't resist.
Well first of all you question design and as a designer of things... and I think I can speak for all engineers out there on this one... Any failure to attain true position on any component certainly wasn't any fault of mine...!! That would be like saying 2 + 2 doesn't always equal 4... ! Numbers on a print are just that... numbers. A component is either to the print or it is not.
I'm guessing this might be part of a homework assignment and board policy says "no helping out with homework." Or something like that. ...but I think I was vague enough that we'll be O.K. on this one.