According to your attachment, there're only excess limitations for both regular tax and AMT.

The IRS does not refer to the statements for excess limitations but the actual F.1116.  We always get copies of at least the last 3 years' returns for our records and also copies of earlier years if we need to source income for stock options.

Having said that, only the excess limitation for 2017 is relevant and only if your client has excess foreign tax credit from 2018 to carryback.

"in the event there is foreign income to offset any carryovers" - Just to be clear, foreign-source compensation only creates limitation, which does not carry back or forward.

As for your client, I still think it is an unusually large limitation your client had in 2017 unless your client was in one of those situations described.  I would take a second look if I were you, especially if your client self-prepared.

Good luck.