Ameridan, thanks for that pointer that the Discover scrubber was primarily fixing up the FITID.
Regarding the Discover scrubber, I looked at it. Some nice elegant coding features, and it looks like it will do the job of avoiding duplicate FITIDs. It now appears to me that it will always produce the same FITID for a given transaction
when there are different time periods involved.
Initially I had missed the fact that the first part of the existing FITID was maintained, and only the sequencing part was modified. Brilliant! and concise.
Since the Citibank bank FITIDs have a date followed by a 4-digit sequence number, then it could indeed be based on a slight modification of the Discover CC. This presumes that the order of transactions for a given date would always be the same, and
that seems to be the case.
If making an FITID from scratch in a scrubber if I did not presume the order would totally stay the same, it seems to me that the date, amount, in addition to a sequence number, would let you keep FITIDs that are both unique and consistent.