Having worked in superannuation systems over the past 30 years, including a few of the systems mentioned above, and particularly in migrating from one system to another, one field that's rarely migrated is total contributions to date because it's never used in any legislative context.
The last one I worked on had been going since 1990 and the administrators wanted to migrate all transactions. It fell apart because the new system validated every piece of data, and having been written in 2009, didn't include all the legislative conditions that applied before 2009, particularly the massive change in 2007. This particularly applied to allocated pensions.
They ended up only migrating data from July 2008, and using an opening balance at 30 June 2008.
There was no way they were going to be able to calculate how much a member had contributed, without going back to the original archaic system, and of course, they didn't want to continue paying licence fees for that system.