how to decode the sequence number

The cars were not built in VIN order as stated previously.

Hamtramck as an example had two assembly lines, did they build odd number VIN cars on one line & even on the other and ensure that they were built in exact VIN order?

Nope.

Cars with VINs very close together at times were not even built the same month! The dates on the Mylar door stickers show the actual build month, so if you see enough of them this becomes very obvious.