In Advance Steel 2016 some bolt lengths were approximated to a value that didn't match the value dictated in the bolt standards (available in Management Tools). This issue has been corrected.
For models that were saved in Advance Steel 2016, it is highly advisable to use the "Update bolts" command when first opening the model in Advance Steel 2016 with Update Release 2:
This command will update the lengths of all bolts in the model, whether they are created by automatic connections or independently.