Cisco Firewall :: Management Port Routing On ASA5525x?

I've got a client with a Management Port set up for Out-of-Band management. Here's the configuration of the interface and some relevant static routes:
 
interface Management0/0
description MGT
speed 100
duplex full
nameif Mgt

[code]...
 
The route through Mgt interface is required as my client accesses the device from a subnet that isn't local to M0/0.Unfortunately, now any traffic originating from outside and destined to 10.48.0.0/16 is choosing the Mgt interface. I had thought that the 'management-only' keyword prevents this from happening (traffic traversing between interfaces).
 
There is a broad scope of /16 addresses on the 'inside' so just swapping destinations won't work (the client wants to avoid a routing table with 50+ static entries, understandably)My temporary solution was to do this:
 
route inside 10.0.0.0 255.128.0.0 10.38.103.1
route inside 10.128.0.0 255.128.0.0 10.38.103.1
route Mgt 10.0.0.0 255.0.0.0 10.38.100.254
  
If 'management-only' doesn't prevent traffic from using the Mgt interface, what is the point of the command?