Serialization - alphanumeric

I have down Numeric Only serialization, but I have a customer asking for alphanumerix.

NXSN1YYWWXX

YY = Year
WW = Week
XX: if I am serializing 102 units…assumption is it goes from 00-99 for 100 units. Will it then go to 0A, 0B? Then all the way to 0Z…10, 11, 1A, …