Before I retired from Dodge/Cummins repair , the shop I was working for would be re-programing ECM's daily . The updates are not always the be all and end all for mileage and performance, and once performed cannot always be undone.
If I had $5 for every owner that came back swearing that we'd ruined his trucks mileage /performance I could have retired a year sooner.
JMHO: If it isn't broken , don't try to fix it.