I found this on cardomain.com Seems that the Y21 code is a valid code.

Y14 Sold Car Order

Y15 Direct Sale

Y16 Sales Bank Order

Y17 Corporate Lease Car System

Y21 Special Headers & Tag Instructions

Y22 Corporate Lease Car - Executive

Y23 California Package Edit Waiver

Y24 C.L.C. Lease Car - Direct Leasing

Y25 Special Driveaway

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