The buses are bought in different batches. Therefore if the
manufacturer had chosen to use different cushion for them for some
reasons, they will be different.
I am assuming you are comparing between Lance 211 and Mercedes O405
Volgren.
Dennis Lance 245 are bought from UMW Malaysia. Therefore, the
design would be more inclined to Malaysian Bus Companies'
needs.
You also can't expect all the buses of different makes and models
being the same right?