I am tempted to say 0.01 is probably less than the margin of error they had when the calculated those expansion rate in the first place.
Who ever measure it did not have the leisure to take a meaningful reading every few minutes to compute their mean value. I also doubt different shapes were taken into account.

The following book has some info on oil finishes and wood protection. I think it will help a little. it start around page 20 :
http://woodtools.nov.ru/books/Understanding_Wood_Finishes.pdf

Abbas, Castro Valley, CA