How best to set sill plates with anchor bolts on poured concrete foundation for modular installation?

As I understand anchor bolts must be hidden below the level of top plate for modular boxes to be placed without obstruction. One way to achieve it is to have anchor bolts approximately 3 inches above foundation and to lay 2 sill plates (2'' each ) on top of each other. I am wondering if there is a way to use only one pressure treated sill plate instead? Thanks.