It basically means that if your documentation (the size you want built) differed by more than 10% in the properties noted from that which was analysed, then you should be updating the analysis to the correct sizes.
I believe its meant to allow for some minor tweaking of member properties, say rationalising say concrete member sizes to the nearest 1/2" rather than 1/4" which analysis might have been based on. Make too many changes, or larger changes then you are obliged to revisit the analysis with these updates included.