I am not familiar with the Holland Tunnel specifically but are there other restrictions that might block a commercial vehicle from being allowed through that tunnel? Often it is a separate restriction, rather than just height that can cause a reroute.
A quick search for https://www.bing.com/search?q=holland+tunnel+restrictions gives a third result that "Holland Tunnel The following restrictions are in place until further notice: In Both Directions: NO TRACTOR-TRAILERS, THREE-AXLE DUAL-UNIT TRUCKS, OR TRUCKS WITH FOUR OR MORE AXLES. Only two and three-axle single-unit trucks allowed. "
You may need to provide a clearer definition of the vehicle as I believe truck routing will err on the side of caution if a value is not defined.