Piltdown man,
Don't believe it!! Your engineer definetly was having a laugh. Fan blades are reworked according to the maintenace manual. If vibration increases a read out off the AVM box is required and said AVM box wil produce a list off balance screws which need to be changed to reduce the vibration. Never in my time as an engineer have i taken out a lump off the opposite blade.
Mach Trim,
The only place you will find the information about fan inspection and allowable damage is in the Aircraft Maintenance Manual. Airbus produces this on a cd-rom so maybe you can ask your engineer if you can have a copy. However if you receive a copy be warned that this information is NOT updated and limits can change. So you can use it as a rough guide but NOT to dispatch an aircraft. Always ask somebody with the latest update of the limits to have a look.
Regards, FT