hi cheryl,

we have experienced the same issue. to the best of my knowledge there are no features in the core that handle this. i ended up writing something to deal with this if you want to try. an admin action that will compare the fields present in all instances of file-based assays against their XML definitions. it gives you the option to add missing fields, and change datatype. it does the later by renaming the existing field and adding a new one with the right datatype.

if you're interested, you will need to install the laboratory module, which is part of DISCVR (https://github.com/bbimber/discvr). these modules are designed for other purposes, but they include a number of admin helpers along these lines. once installed, go to the admin console, pick DISCVR Admin, then 'Synchronize Assay Fields'. this is tested code that we've used on many servers; however, it reaches around normal LabKey UI, so please backup your DB first and understand that this is at your own risk.

-ben