"Client has not been any help, but I will try again."

Yes, because those are a lot of assumptions.

There can be more than one plan, so not everything here has to be from one provision. There can be prior W2 values for FMV for something now vested and sold, so basis isn't even part of what you see on that current W2; it happened years ago (typically 5 years vesting).

If this employer is not available via an HR person, and this employee has no literature about this, and the statements have no title or other documents (summary plan info), then perhaps there is a more informed co-worker that will be able to help. There is no Standard for Box 14 notation. No one here can help with that translation, or the history of the transactions that applies to the current events.

You might be trying to combine things that stand separate.