What is the difference between Engineer$-$to$-$order and Make$-$to$-$order?

Make$-$to$-$order and Engineer$-$to$-$order are similar except Make$-$to$-$order takes longer due to manufacturing of parts.

Make$-$to$-$order and Engineer$-$to$-$order are basically synonyms and there is no real difference.

Engineer$-$to$-$order requires more customization and Make$-$to$-$order is based upon a standard design with some changes.